UNIT #3: Electrons in Atoms/Periodic Table and Trends

Name:_________________________________ Period:_________

UNIT #3: Electrons in Atoms/Periodic Table and Trends

1. ELECTRON CONFIGURATION

Electrons fill the space surrounding an atom’s nucleus in a very specific order following the rules listed below:

a) Aufbau Principle: Each electron occupies the lowest energy orbital available. The orbitals closest to the nucleus have the lowest energy; the orbitals farthest from the nucleus have the highest energy.

Order of increasing energy: 1s→2s→2p→3s→3p→4s→3d→4p→5s→4d→5p→6s→4f→5d→6p→7s→5f→6d→7p

b) Pauli Exclusion Principle: A maximum of two electrons may occupy a single orbital, but only if the electrons have opposite spins. Each electron in an atom has an associated spin, similar to the way a top spins on its axis. Like a top, an electron can spin in only one of two directions. In an orbital diagram, this is represented by an arrow up ↑ for an electron spinning in one direction, and an arrow down ↓ for an electron spinning in the opposite direction.

c) Hund’s Rule: Single electrons with the same spin must occupy each equal-energy orbital before additional electrons with opposite spins can occupy the same orbitals. This is due to the fact that electrons carry like negative charges and thus, repel each other. An electron will pair up with another electron within a given sublevel (s,p,d,f) only when necessary and in doing so, adopts the opposite spin.

Key Terms: 1. Principle Energy/Quantum Level: Major energy levels surrounding the nucleus of an atom. Consists of n=1, n=2, n=3, n=4, n=5, n=6, n=7 (corresponding to periods 1 through 7 on the periodic table).

2. Energy Sublevels: Within a principle energy level, electrons occupy sublevels labeled s, p, d or f according to the shape of the atom’s orbital. S-orbitals are spherical in shape; p- orbitals are dumbbell shaped; d and f orbitals have varying shapes.

3. Orbitals: Within a sublevel, electrons occupy a specific number of orbitals, each of which contain up to one pair of electrons with opposite spins. The number of orbitals within a sublevel is as follows: S-sublevel: Contains one orbital which contains a maximum of 2 electrons. P-sublevel: Contains three orbitals, each of which contains a maximum of 2 electrons. Maximum number of p-sublevel electrons is six. D-sublevel: Contains five orbitals, each of which contains a maximum of 2 electrons. Maximum number of d-sublevel electrons is ten. F-sublevel: Contains seven orbitals, each of which contains a maximum of 2 electrons. Maximum number of f-sublevel electrons is fourteen.

4. Valence Electrons: Electrons occupying the outermost principle energy level.

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Electron Configuration: Denotes the filling of electrons according to the rules listed above. The configurations depict the principle energy level of each electron (coefficient 1 through 7), followed by the sublevel (s,p,d,f), followed by a superscript that represents the number of electrons. NOTE: Electrons filling sublevel d drop one energy level and electrons filling sublevel f drop two energy levels.

Order of filling sublevels according to aufbau principle: Period 1 atoms: 1s Period 2 atoms: 1s, 2s, 2p Period 3 atoms: 1s, 2s, 2p, 3s, 3p Period 4 atoms: 1s, 2s, 2p, 3s, 3p, 4s, 3d, 4p Period 5 atoms: 1s, 2s, 2p, 3s, 3p, 4s, 3d, 4p, 5s, 4d, 5p Period 6 atoms: 1s, 2s, 2p, 3s, 3p, 4s, 3d, 4p, 5s, 4d, 5p, 6s, 4f, 5d, 6p Period 7 atoms: 1s, 2s, 2p, 3s, 3p, 4s, 3d, 4p, 5s, 4d, 5p, 6s, 4f, 5d, 6p, 7s, 5f, 6d, 7p

Ex. He: 1s2 (2 electrons in atom) Ne: 1s22s22p6 (10 electrons in atom) Ar: 1s22s22p63s23p6 (18 electrons in atom) Kr: 1s22s22p63s23p64s23d104p6 (36 electrons in atom) Xe: 1s22s22p63s23p64s23d104p65s24d105p6 (54 electrons in atom) Rn: 1s22s22p63s23p64s23d104p65s24d105p66s24f145d106p6 (86 electrons in atom) NOTE: In these examples, each atom (other than helium) contains 8 valence electrons. This is the stable octet that all other atoms strive to achieve. When atoms become ions, they either lose electrons (metals) or gain electrons (non-metals) to achieve a stable principle energy level similar to their closest noble gas.

More examples of neutral atoms versus their corresponding ions: Be 1s22s2 neutral beryllium atom with 4 electrons Be2+ 1s2 beryllium ion with 2 electrons (lost 2)

Na 1s22s22p63s1 neutral atom with 11 electrons Na+ 1s22s22p6 sodium ion with 10 electrons (lost 1)

O 1s22s22p4 neutral oxygen atom with 8 electrons O2- 1s22s22p6 oxide ion with 10 electrons (gained 2)

P 1s22s22p63s23p3 neutral phosphorous atom with 15 electrons P3- 1s22s22p63s23p6 phosphide ion with 18 electrons (gained 3) Orbital Diagrams: Denotes each orbital within a sublevel and the electrons occupying those orbitals (indicated by an up arrow ↑ or a down arrow ↓). Electrons fill orbitals singularly at first, then pair as necessary with an opposite spin. Ex. 2p4 ↑↓ ↑ ↑ 2p 2p 2p 3d7 ↑↓ ↑↓ ↑_ ↑_ ↑_ 3d 3d 3d 3d 3d

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2. ELEMENTS AND THE PERIODIC TABLE

a) An element is a pure substance that cannot be separated into simpler substances by physical or chemical means.

b) Each element has a unique chemical name and symbol. The chemical symbol consists of one, two or three letters: the first letter is always capitalized and the remaining letter(s) are always lowercase.

c) Seven elements occur in nature as diatomic molecules (2 atoms) because the molecules formed are more stable than the individual atoms. They are Br2, I2, N2, Cl2, H2, O2, F2. Remember it as BrINClHOF.

d) On earth, 91 elements are naturally occurring and their abundance in the universe varies. e) The Periodic Table organizes the elements according to increasing atomic number.

1. Elements are arranged in vertical columns called groups or families. Each group is numbered 1 through 18.

2. Groups 1, 2, 13, 14, 15, 16, 17 and 18 are often referred to as the main group, or representative elements, because they possess a wide range of chemical and physical properties.

3. Groups 3, 4, 5, 6, 7, 8, 9, 10, 11 and 12 are referred to as the transition elements. 4. Elements in the same group have similar chemical and physical properties.

5. Elements are arranged in horizontal rows called periods. Beginning with hydrogen in period 1, there are a total of 7 periods.

f) Classification of Elements 1. Metals are elements that are generally shiny when smooth and clean, solid at room

temperature, and good conductors of heat and electricity. Most metals are malleable (can be pounded into thin sheets) and ductile (can be drawn into wires).

a) Used to transmit electrical power, ex. copper. b) Can be formed into coins, tools, fasteners and wires. c) Group 1 elements (except hydrogen) are known as the alkali metals.

d) Group 2 elements are known as the alkaline earth metals. e) Both alkali and alkaline earth metals are chemically reactive, with alkali

metals being the more reactive group. f). Groups 3 through 12 elements are divided into 1. transition metals-located in periods 4 through 7. 2. inner transition metals-two sets of inner transition metals, known as the

lanthanide and actinide series, appear at the bottom of the periodic table and are usually offset from the numbered periods. These elements are phosphors, substances that emit light when struck by electrons.

2. Nonmetals are elements that are generally gases or brittle, dull-looking solids. They are poor conductors of heat and electricity. The only non-metal that is a liquid at room temperature is bromine.

a) Group 17 elements are the halogens. These are the most reactive non-metals. b) Group 18 elements are the noble gases-extremely unreactive due to the most

stable and complete electron configuration. 3. Metalloids or semimetals are elements with physical and chemical properties of both

metals and nonmetals. a) Located on the right hand side of the periodic table and form a stair-step

pattern between the transition metals and the nonmetals. b) Consists of B, Si, Ge, As, Sb, Te and At.

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3. COMPOUNDS AND LAWS OF DEFINITE/MULTIPLE PROPORTI ONS

a) A compound is a combination of two or more different elements that are combined chemically. Much of the matter of the universe are compounds; there are approximately 10 million known compounds.

Examples are water, table salt, table sugar, aspirin. b) Compounds or elements that occur alone are referred to as pure substances. Compounds

or elements that occur in combination with other compounds or elements are referred to as mixtures. 1. Homogenous mixture-one that has a uniform composition throughout and always has

a single phase; can be separated by physical means such as distillation (a technique used to separate mixtures based on the differences in the boiling points of the substances) or by evaporation (removing liquid component from solid component); homogenous mixtures are also referred to as solutions.

Ex. salt water, sugar water, lemonade, gasoline, steel. 2. Heterogeneous mixture-one that does not have a uniform composition and in which

the individual substances remain distinct; can be separated by physical means such as filtration (technique that uses a porous barrier to separate solids from liquids). Ex. sand and water, dirt, Italian salad dressing.

c) Law of Definite Proportions 1. Elements making up compounds always combine in definite proportions by mass.

Regardless of the amount of a given compound, it is always composed of the same elements in the same proportion by mass.

d) Law of Multiple Proportions 1. When different compounds are formed by combinations of the same elements,

different masses of one element combine with the same relative mass of the other element in a ratio of small whole numbers.

2. Examples: a) Water is H2O: 2 parts hydrogen to 1 part oxygen Hydrogen Peroxide is H2O2: 2 parts hydrogen to 2 parts oxygen Both compounds are comprised of the same elements; however, H2O2 differs from

H2O in that it has twice as much oxygen. When we compare the mass of oxygen in H2O2 to the mass of oxygen in H2O, we get the ratio 2:1.

b) Methane is CH4; Carbon = 12amu and Hydrogen = 4amu; Cmass : Hmass = 12:4 or 3:1 Ethane is C2H6; Carbon = 24amu and Hydrogen = 6amu; Cmass : Hmass = 24:6 or 4:1

4. PERIODIC TABLE TRENDS

a) Atomic Radius 1. The radius of an atom is one-half the distance between the nuclei of two atoms of the

same element when the atoms are joined; it is comparable to the radius of a circle which is the length of a line from the center of the circle to its edge.

2. Radius decreases as you move across a period. As you move across a period, each successive element has one additional proton in its nucleus; therefore, the positive nuclear pull increases on the negative electrons surrounding the nucleus, causing the radius to decrease.

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3. Radius increases as you move down a group. As you move down a group, each successive element has an additional energy level surrounding its nucleus and therefore, the radius increases.

b) Ionic Radius 1. An ion is an atom or a bonded group of atoms that has a positive charge (due to loss of

electrons) or negative charge (due to gaining electrons). 2. When atoms lose electrons to become positive ions, their radius decreases. The loss

of valence electrons from the outermost energy level results in an empty valence shell and therefore, the next level down becomes the ion’s outermost energy level; therefore, the radius decreases.

3. When atoms gain electrons to become negative ions, their radius increases. The addition of electron(s) to the outermost energy level results in additional repulsive forces between the like-charged electrons. This causes the electrons to move further apart and effectively, increases the ion’s radius.

c) Ionization Energy 1. Ionization energy is the energy required to remove an electron from a gaseous atom. It

is an indication of how strongly the atom’s nucleus is pulling on its electrons. A higher ionization energy value means more energy is required to remove an electron, indicating a strong nuclear pull. A lower ionization energy value means less energy is required to remove an electron, indicating a weaker nuclear pull.

2. Ionization energy increases as you move across a period. As the number of protons increases across a period, the nuclear pull increases.

3. Ionization energy decreases as you move down a group. As energy levels are added moving down a group, the valence electrons become farther removed from the nuclear pull and its effect decreases. Also, an increase in the number of electrons between the outermost energy level and the nucleus causes what is termed a “shielding effect,” that is, the nuclear pull is diminished due to the intervening electrons.

d) Electronegativity 1. Electronegativity indicates the ability of an atom to attract electrons in a chemical bond. 2. Electronegativity increases as you move across a period. An increase in the number

of protons in the nucleus of each successive atom results in a stronger nuclear pull on the atom’s own electrons and on another atom’s electrons in a chemical bond.

3. Electronegativity decreases as you move down a group. An increase in the distance between the nucleus and the outermost electrons results in a weaker nuclear pull on the atom’s own electrons and on another atom’s electrons in a chemical bond.

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ho

wn

.

17

. M

ake

ob

serv

atio

ns

abo

ut

the

gra

ph

in

ter

ms

of

the

rela

tiv

e en

erg

ies

of

the

elec

tro

ns

and

th

eir

rela

tio

nsh

ip t

o e

ach

oth

er.

18

. B

ased

on

yo

ur

resp

on

ses

fro

m t

he

pre

vio

us

qu

esti

on

s h

ow

man

y ‘

gro

up

s’ (

lev

els

or

shel

ls)

of

elec

tro

ns

are

sho

wn

fo

r A

rgo

n?

19

. In

dic

ate

the

nu

mb

er o

f el

ectr

on

s in

eac

h g

roup

/lev

el t

hat

yo

u i

den

tifi

ed?

Ele

ctro

n

Rem

ov

ed

Ele

ctro

n

En

erg

y

(kJ

mo

l –

1)

1

−1

52

1

2

−2

66

6!

3

−3

93

1!

4

−5

75

1!

5

−7

23

8!

6

−8

78

1!

7

−1

19

95!

8

−1

38

42!

9

−4

07

60!

10

−

46

18

6!

11

−

52

00

2!

12

−

59

65

3!

13

−

66

19

8!

14

−

72

91

8!

15

−

82

47

2!

16

−

88

57

6!

17

−

39

76

04!

18

−

42

70

65!

Ad

apte

d a

nd

mo

dif

ied

fro

m J

oh

n G

eld

er’s

DR

AF

T V

ER

SIO

N.

20

. O

n t

he

gra

ph

bel

ow

dra

w a

ho

rizo

nta

l li

ne

(to

th

e ri

gh

t o

f th

e y

-ax

is)

that

rep

rese

nts

an

av

erag

e en

erg

y l

evel

fo

r ea

ch o

f th

e g

roup

s o

f el

ectr

on

s th

at y

ou

iden

tifi

ed.

Lab

el t

he

lev

els

1,

2,

etc.

… b

egin

nin

g f

rom

th

e lo

wes

t en

erg

y l

evel

.

Wh

at d

o t

hes

e li

nes

rep

rese

nt?

2

1. H

ow

wo

uld

yo

u d

escr

ibe

the

rela

tiv

e en

erg

y s

epar

atio

n o

f th

ese

ener

gy

lev

els?

22

. A

n e

lect

ron

fro

m w

hic

h l

evel

req

uir

es

•

the

least

am

ou

nt

of

ener

gy

to

rem

ov

e?

•

Th

e la

rges

t am

ou

nt

of

ener

gy

to

rem

ov

e?

Ad

apte

d a

nd

mo

dif

ied

fro

m J

oh

n G

eld

er’s

DR

AF

T V

ER

SIO

N.

Des

crib

e th

e el

ectr

on

str

uct

ure

(lo

cati

on

of

the

elec

tro

n)

of

the

ato

m.

Co

nsi

der

usi

ng

som

e o

r al

l o

f th

e fo

llo

win

g t

erm

s in

yo

ur

des

crip

tio

n;

nu

cleu

s, e

lect

ron

, en

erg

y,

dis

tan

ce,

lev

el, p

roto

n,

shel

l, a

rran

gem

ent,

att

ract

ion

, re

pu

lsio

n, p

osi

tiv

e, n

egat

ive,

ch

arg

e,

loca

tio

n.

PA

RT

II:

Do

all

ele

ctro

ns

in t

he

sam

e le

vel

ha

ve t

he

sam

e en

erg

y?

On

e im

po

rtan

t co

ncl

usi

on

bas

ed o

n t

he

firs

t io

niz

atio

n e

ner

gy

exp

erim

enta

l d

ata

is t

hat

elec

tro

ns

in h

igh

er s

hel

ls r

equ

ire

less

en

erg

y t

o r

emo

ve.

We

hav

e ex

amin

ed e

xp

erim

enta

l

dat

a th

at r

elat

es t

he

ener

gy

req

uir

ed t

o r

emo

ve

an e

lect

ron

to

th

e sh

ell

the

elec

tro

n

occ

up

ies.

•

In w

hic

h s

hel

l d

oes

an

ele

ctro

n r

equ

ire

mo

re e

ner

gy

to

rem

ov

e, a

n e

lect

ron

in

th

e

seco

nd

sh

ell

or

the

fou

rth

sh

ell?

An i

nte

rest

ing

qu

esti

on

th

at c

ann

ot

be

answ

ered

fro

m t

he

exp

erim

enta

l d

ata

of

the

firs

t

ion

izat

ion

en

erg

y i

s…

Do

all

ele

ctro

ns

in t

he

sam

e sh

ell

req

uir

e th

e sa

me

am

ou

nt

of

ener

gy

to r

emo

ve?

We

CA

N a

nsw

er t

his

qu

esti

on

if

we

loo

k a

t p

ho

toel

ectr

on

sp

ectr

osc

op

y (

PE

S)

dat

a fo

r

the

ato

ms.

In

a p

ho

toel

ectr

on

sp

ectr

osc

op

y e

xp

erim

ent

any

ele

ctro

n c

an b

e io

niz

ed w

hen

the

ato

m i

s ex

cite

d.

Lik

e w

ith

th

e fi

rst

ion

izat

ion

, o

nly

on

e el

ectr

on

is

rem

ov

ed f

rom

th

e

ato

m.

Ho

wev

er i

n a

PE

S e

xp

erim

ent

it c

an b

e A

NY

ele

ctro

n,

no

t ju

st t

he

elec

tro

n t

hat

req

uir

es t

he

leas

t am

ou

nt

of

ener

gy

to

rem

ov

e.

Ad

apte

d a

nd

mo

dif

ied

fro

m J

oh

n G

eld

er’s

DR

AF

T V

ER

SIO

N.

Ex

amin

e th

e P

ES

sp

ectr

um

fo

r h

yd

rog

en s

ho

wn

in

th

e fi

gu

re.

Th

e la

bel

on

th

e y-a

xis

is

ener

gy

an

d t

he

un

its

are

in m

egaj

ou

les(

M J

mo

l –

1)

1.

Wh

at d

oes

th

e x-a

xis

dep

ict?

Exp

lain

.

Ad

apte

d a

nd

mo

dif

ied

fro

m J

oh

n G

eld

er’s

DR

AF

T V

ER

SIO

N.

2.

Wh

at i

s th

e re

lati

on

ship

bet

wee

n t

he

ph

oto

elec

tro

n s

pec

tru

m a

nd

th

e fi

rst

ion

izat

ion

en

erg

y f

or

hy

dro

gen

?

Hel

ium

is

nex

t, b

ut

bef

ore

lo

ok

ing

at

its

ph

oto

elec

tro

n s

pec

tru

m a

nsw

er t

he

foll

ow

ing

qu

esti

on

s:

3.

Ho

w m

any

ele

ctro

ns

do

es h

eliu

m h

ave

in i

ts f

irst

sh

ell?

4.

Ref

er b

ack

to

Par

t I

of

this

act

ivit

y,

and

ob

tain

th

e fi

rst

ion

izat

ion

en

erg

y f

or

a

hel

ium

ato

m.

Can

yo

u p

red

ict

wh

at t

he

PE

S w

ou

ld l

oo

k l

ike

if

a.

the

sam

e am

ou

nt

of

ener

gy

is

req

uir

ed t

o r

emo

ve

each

of

the

elec

tro

ns?

b.

dif

fere

nt

amo

un

ts o

f en

erg

y a

re r

equ

ired

to

rem

ov

e ea

ch e

lect

ron

?

Go

to

bac

k t

o t

he

pre

vio

us

fig

ure

an

d s

ket

ch b

oth

sce

nar

ios.

Ad

apte

d a

nd

mo

dif

ied

fro

m J

oh

n G

eld

er’s

DR

AF

T V

ER

SIO

N.

Ex

amin

e th

e P

ES

fo

r h

eliu

m a

nd

co

mp

are

it t

o y

ou

r p

red

icti

on

fro

m t

he

pre

vio

us

qu

esti

on

.

5

. E

xp

lain

th

e re

lati

ve

ener

gy

of

the

pea

k(s

) an

d t

he

nu

mb

er o

f el

ectr

on

s re

pre

sen

ted

by

eac

h p

eak

in

th

e P

ES

fo

r h

eliu

m a

nd

fo

r h

yd

rog

en.

6.

Fo

r li

thiu

m

a.

Ho

w m

any

ele

ctro

ns

do

es l

ith

ium

hav

e?

b.

Wh

at s

hel

ls (

lev

els)

do

th

ose

ele

ctro

ns

occ

up

y?

7.

Pre

dic

t w

hat

yo

u e

xp

ect

the

PE

S f

or

lith

ium

to

lo

ok

lik

e. (

No

te:

yo

u d

o n

ot

hav

e

to p

red

ict

the

exac

t en

erg

ies

of

each

ele

ctro

n,

yo

u c

an m

ake

a re

aso

nab

le e

stim

ate

bas

ed o

n t

he

firs

t io

niz

atio

n e

ner

gie

s fo

r li

thiu

m a

nd

hel

ium

- r

efer

bac

k t

o P

art

I

of

this

act

ivit

y.

Ad

apte

d a

nd

mo

dif

ied

fro

m J

oh

n G

eld

er’s

DR

AF

T V

ER

SIO

N.

L

oo

k a

t th

is P

ES

an

d c

om

par

e it

to

th

e p

red

icti

on

yo

u m

ade

in t

he

pre

vio

us

qu

esti

on

.

8.

Fo

r ea

ch p

eak

in

th

e P

ES

of

lith

ium

, id

enti

fy t

he

shel

l th

e el

ectr

on

s re

pre

sen

ted

by

that

pea

k o

ccup

y.

Be

sure

to

co

mm

ent

abo

ut

the

rela

tiv

e en

erg

y o

f th

e p

eak

(s)

and

the

nu

mb

er o

f el

ectr

on

s fo

r ea

ch p

eak

fo

r L

i.)

Th

e n

ext

elem

ent

in t

he

Per

iod

ic T

able

is

ber

yll

ium

.

9.

Ho

w m

any

ele

ctro

ns

do

es b

ery

lliu

m h

ave

and

wh

at s

hel

ls d

o t

ho

se e

lect

ron

s

occ

up

y?

10

. F

or

the

PE

S f

or

ber

yll

ium

pre

dic

t

a.

ho

w m

any

pea

ks

b.

the

nu

mb

er o

f el

ectr

on

fo

r ea

ch p

eak

c.

esti

mat

e th

e re

lati

ve

ener

gie

s.

Ad

apte

d a

nd

mo

dif

ied

fro

m J

oh

n G

eld

er’s

DR

AF

T V

ER

SIO

N.

T

he

nex

t el

emen

t in

th

e P

erio

dic

Tab

le i

s b

oro

n.

11

. H

ow

man

y e

lect

ron

s d

oes

bo

ron

hav

e an

d w

hat

sh

ells

do

th

ose

ele

ctro

ns

occ

up

y?

12

. F

or

the

PE

S f

or

bo

ron

pre

dic

t

a.

ho

w m

any

pea

ks

b.

the

nu

mb

er o

f el

ectr

on

(s)

for

each

pea

k

c.

esti

mat

e th

e re

lati

ve

ener

gie

s

Ad

apte

d a

nd

mo

dif

ied

fro

m J

oh

n G

eld

er’s

DR

AF

T V

ER

SIO

N.

Bel

ow

is

the

PE

S f

or

bo

ron

.

13

. B

rief

ly d

escr

ibe

ho

w t

o i

nte

rpre

t th

e P

ES

fo

r b

oro

n.

14

. P

red

ict

wh

at c

han

ges

in

th

e P

ES

yo

u w

ou

ld e

xp

ect

to s

ee g

oin

g a

cro

ss p

erio

d 2

of

the

per

iod

ic t

able

, fr

om

car

bo

n t

o n

eon

? L

oo

k a

t th

e P

ES

fo

r th

ese

seco

nd

per

iod

elem

ents

.

Ad

apte

d a

nd

mo

dif

ied

fro

m J

oh

n G

eld

er’s

DR

AF

T V

ER

SIO

N.

Bel

ow

is

the

PE

S f

or

the

per

iod

2 e

lem

ents

fro

m b

oro

n t

o n

eon

.

Ad

apte

d a

nd

mo

dif

ied

fro

m J

oh

n G

eld

er’s

DR

AF

T V

ER

SIO

N.

15

. A

nsw

er t

he

foll

ow

ing

qu

esti

on

s af

ter

loo

kin

g a

t th

e P

ES

fo

r h

yd

rog

en t

hro

ug

h

neo

n. a.

Wo

uld

yo

u a

gre

e o

r d

isag

ree

wit

h t

he

foll

ow

ing

sta

tem

ent?

Exp

lain

yo

ur

answ

er.

‘Th

e el

ectr

ons

in t

he

seco

nd

sh

ell

all

ha

ve t

he

sam

e en

erg

y.’

b.

Ho

w m

any

‘su

bsh

ells

’ ar

e fo

un

d i

n t

he

seco

nd

sh

ell?

c.

Ho

w m

any

‘su

bsh

ells

’ ar

e fo

un

d i

n t

he

firs

t sh

ell?

d.

Ho

w m

any

ele

ctro

ns

are

in e

ach

sub

shel

l in

th

e se

con

d s

hel

l? I

n t

he

firs

t

shel

l?

e.

Mo

vin

g s

yst

emat

ical

ly f

rom

lit

hiu

m t

o n

eon

;

i.

Ho

w m

any

ele

ctro

ns

are

in t

he

firs

t sh

ell?

ii.

Wh

at h

app

ens

to t

he

ener

gy

req

uir

ed t

o r

emo

ve

an e

lect

ron

in

th

e

firs

t sh

ell

mo

vin

g f

rom

lef

t to

rig

ht

in t

he

seco

nd

per

iod

? S

up

po

rt

yo

ur

ob

serv

atio

n w

ith

an e

xp

lan

atio

n.

iii.

Wh

at h

app

ens

to t

he

ener

gy

of

the

elec

tro

ns

in t

he

ou

ter

mo

st

shel

l?

16

. L

oo

k a

t th

e P

ES

fo

r th

e el

emen

ts i

n t

he

thir

d p

erio

d (

sod

ium

– a

rgo

n)

and

des

crib

e y

ou

r ob

serv

atio

ns.

An

y s

urp

rise

s? E

xp

lain

.

A n

ota

tio

n h

as b

een

ag

reed

up

on

fo

r w

riti

ng

an

ele

ctro

n c

on

fig

ura

tio

n t

o i

den

tify

th

e

loca

tio

n o

f th

e sh

ell

and

sub

shel

l o

f ea

ch e

lect

ron

in

an

ato

m.

Sh

ells

are

lab

eled

wit

h a

nu

mb

er;

1,

2,

3,

etc.

an

d s

ub

shel

l ar

e la

bel

ed w

ith

let

ters

; s,

p, d

, an

d f

. E

ver

y s

hel

l

con

tain

s an

s s

ub

shel

l.

17

. W

rite

th

e co

mp

lete

ele

ctro

n c

on

fig

ura

tio

n f

or

the

firs

t te

n e

lem

ents

in

th

e p

erio

dic

tab

le?

Lo

ok

at

the

PE

S f

or

po

tass

ium

, ca

lciu

m a

nd

sca

nd

ium

.

18

. E

xp

lain

wh

at h

app

ens

in t

he

PE

S f

or

scan

diu

m t

hat

has

no

t o

ccu

rred

in

an

y

elem

ent

pri

or.

19

. If

on

e el

ectr

on

is

rem

ov

ed f

rom

sca

nd

ium

, w

hic

h e

lect

ron

(id

enti

fy t

he

shel

l an

d

sub

shel

l) r

equ

ires

th

e le

ast

amo

un

t o

f en

erg

y t

o r

emo

ve?

Nam

e:_

__

__

__

__

__

__

__

__

__

__

__

__

__

__

__

__

_D

ate:

__

__

__

__

__

__

__

__

__

__

_P

erio

d:_

__

__

Pag

e 1

of

4

© 2

004

Hig

h S

choo

l T

echn

olo

gy I

nit

iati

ve

(HS

TI)

Ed

uca

tion

al M

ater

ials

: T

he

AT

OM

: S

tru

ctu

re

Bo

hr M

od

el

Worksheet

Dir

ecti

on

s

Dra

w t

he

Bo

hr

Mo

del

s sh

ow

ing

all

th

e el

ectr

on

s in

eac

h e

ner

gy

lev

el.

1.

M

agn

esiu

m c

om

po

un

ds

are

use

d i

n t

he

pro

duct

ion o

f ura

niu

m f

or

nucl

ear

reac

tors

. D

raw

th

e B

oh

r m

od

el f

or

mag

nes

ium

.

Nie

ls B

oh

r

2.

So

diu

m i

s fo

un

d i

n s

alts

th

at c

an b

e u

sed

to

see

d c

lou

ds

to i

ncr

ease

rai

nfa

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Page 1 of 8

Electron Configurations Worksheet

Write the complete ground state electron configurations and orbital notations for the following:

# of e Element (atom) e- configuration Orbital Notations/ diagrams 1) _____ lithium ___________________________ _________________________________ 2) _____ oxygen ___________________________ _________________________________ 3) _____ calcium ___________________________ _________________________________ 4) _____ nitrogen ___________________________ _________________________________ 5) _____ potassium ___________________________ _________________________________ 6) _____ chlorine ___________________________ _________________________________ 7) _____ hydrogen ___________________________ _________________________________ 8) _____ copper ___________________________ _________________________________ 9) _____ neon ___________________________ _________________________________ 10) _____ phosphorous ___________________________ _________________________________ Write the abbreviated ground state electron configurations, noble gas configuration, for the following: # of electrons Element Electron Configuration 11) ______ helium ________________________________________ 12) ______ nitrogen ________________________________________ 13) ______ chlorine ________________________________________ 14) ______ iron ________________________________________ 15) ______ zinc ________________________________________ 16) ______ barium ________________________________________ 17) ______ bromine ________________________________________ 18) ______ magnesium _______________________________________ 19) ______ fluorine __________________________________________ 20) ______ aluminum _______________________________________

Page 2 of 8

Electron Configuration Elements (atoms) and Ions Write the electron configuration and orbital notations for the following Atoms and ions: Element / Ions

Atomic number

# of e- Electron Configuration

F

F1-

O

O-2

Na

Na1+

Ca

Ca+2

Page 3 of 8

Al3+

Al

N

N3-

S2-

Cl1-

K1+

S

Br1-

Mg2+

Page 4 of 8

Electron Configuration Practice

Directions: Write and draw the electron configurations of each of the following atoms. Example: Co : 27 e- 1s2 2s2 2p6 3s2 3p6 4s2 3d7

1. Scandium: 2. Gallium: 3. Silver: 4. Argon: 5. Nitrogen: 6. Lithium: 7. Sulfur:

Co 1s 2s 2p 2p 2p 2p 3s 3p 3p 3p

3d 3d 3d 3d 3d 4s

Page 5 of 8

Electron Position and Configuration

Position: Draw the Electron Position of each of the following atoms. Example:

He:

1. Li 2. C

3. O 4. Ar

Directions: Draw the electron configurations of each of the following atoms. Example:

1. Chlorine: 2. Nitrogen: 3. Aluminum: 4. Oxygen:

5. Sodium: 6. Potassium: 7. Sulfur: 8. Calcium

F 1s 2s 2p 2p 2p 2p

Page 6 of 8

Electron Configuration Practice

In the space below, write the expanded electron configurations (ex. = 1s22s1) of the following elements:

1) Sodium ________________________________________________

2) potassium ________________________________________________

3) chlorine ________________________________________________

4) bromine ________________________________________________

5) oxygen ________________________________________________

In the space below, write the abbreviated electron configurations (ex. Li= [He]2s1) of the following elements:

6) manganese ________________________________________________

7) silver ________________________________________________

8) nitrogen ________________________________________________

9) sulfur ________________________________________________

10) argon ________________________________________________ In the space below, write the orbital notation (arrows) of the following elements:

11) manganese _______________________________________________

12) silver ________________________________________________

13) nitrogen ________________________________________________

14) sulfur ________________________________________________

15) argon ________________________________________________

Determine what elements are denoted by the following electron configurations:

16) 1s22s22p63s23p4 ____________________

17) 1s22s22p63s23p64s23d104p65s1 ____________________

18) [Kr] 5s24d105p3 ____________________

19) [Xe] 6s24f145d6 ____________________

20) [Rn] 7s25f11 ____________________ Determine which of the following electron configurations are not valid:

21) 1s22s22p63s23p64s24d104p5 __________________ 22) 1s22s22p63s33d5 ____________________

23) [Ra] 7s25f8 ____________________ 24) [Kr] 5s24d105p5 ____________________ 25) [Xe] ____________________

Page 7 of 8

Name______________________

Period___________________

Electrons, Valence, and Lewis Dot Structures Chem 544/545 Dr. Brielmann

1. How many electrons are present in:

Helium (He)_____ Carbon (C)_____ Neon (Ne)_____ Sodium (Na)_____ Zinc (Zn)____

2. How many valence electrons are present in:

Helium (He)_____ Carbon (C)_____ Neon (Ne)_____ Sodium (Na)_____

Potassium (K)_____ Fluorine (F)_____ Chlorine _____ Bromine_____

3. Draw Lewis Dot Structures for the following elements:

Helium (He) Carbon (C) Neon (Ne) Sodium (Na)

Ne

4. Correct the following Lewis Dot Structures:

Oxygen Nitrogen Beryllium Fluorine

O N Be F

5. Fill in the following table:

Carbon Carbon anion Carbon cation

number of electrons:

number of valence electrons

Lewis structure

C C- +

S-C-5-3_Periodic Trends Worksheet and KEY

10. For each of the following, circle or highlight the correct element that best matches the statement on the right.

Li Si S metal

N P As smallest ionization energy

K Ca Sc largest atomic mass

S Cl Ar member of the halogen family

Al Si P greatest electron affinity

Ga Al Si largest atomic radius

V Nb Ta largest atomic number

Te I Xe member of noble gases

Si Ge Sn 4 energy levels

Li Be B member of alkali metals

As Se Br 6 valence electrons

H Li Na nonmetal

Hg Tl Pb member of transition metals

Na Mg Al electron distribution ending in s2p1

Pb Bi Po metalloid

B C N gas at room temperature

Ca Sc Ti electron distribution ending in s2d2

Source: http://www.gpb.org/files/pdfs/gpbclassroom/chemistry/periodicTableTrendsWkst.pdf

Unit3NoteQuizQuestions

Unit 3.2: Electron Configuration

1. a

2. a

3. z

4.

5. a

6. a

7. A

8. A

9. A

10.

Unit 3.3: Periodic Trends

1. a

2.

3. A

4. a

5. a

6. a

7. a

8. a

9. a

10.

UNIT #3: Electrons in Atoms/Periodic Table and Trends

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