The Atom and the Periodic Table Chapter 10 and Chapter 11.

The Atom and the Periodic TableChapter 10 and Chapter 11

Objectives

•SPI 0807.9.1 Recognize that all matter consists of atoms

• I can:1. I can recognize that all matter is made of

atoms.2. I can identify the parts of an atom.3. I can identify the charge and location of

each particle in an atom.4. Explain how an atom can be neutral and

how the atom can become charged.

History of Atomic Theory• Democritus – Greek philosopher 400 BCE

Thought you could eventually end up with a particle that could not be cut in half – he called this particle an atom. From Greek word “atomos” meaning “not able to be divided”

Most people did not believe this to be true including Aristotle.

Did not perform experiments to prove theory, it was just an idea

• Democritus was right: matter is made of particles called atoms – the smallest particle into which an element can be divided and still be the same substance

I can recognize that all matter is made of atoms.

Dalton’s Atomic Theory

•John Dalton – British chemist and schoolteacher▫Published his theory in 18031. All substances are made of atoms.

Atoms are small particles that cannot be created, divided, or destroyed.

2. Atoms of the same element are exactly alike and atoms of different elements are different.

3. Atoms join with other atoms to make new substances.


Thomson’s Discovery of Electrons• J. J. Thomson(1897) –

British scientist (awarded Nobel Prize in 1906)

• Proved Dalton’s theory had a mistake: atoms can be divided into smaller parts.▫ Discovered electrons

(e-) – subatomic particle that has a negative charge

• Plum-pudding model▫ Electrons were mixed

throughout an atom

I can recognize that all matter is made of atoms.I can identify the charge and location of electrons in an atom.

Rutherford’s Theory• Ernest Rutherford (1911)–

student of Thomson (awarded Nobel Prize in 1908)▫ Proposed that the center

of the atom is the nucleus – tiny, extremely dense positively charged part of the atom

I can recognize that all matter is made of atoms.I can identify the parts of an atom.

Bohr’s Model• Niels Bohr (1913) – Danish

scientist, worked with Rutherford (awarded Nobel Prize in 1922)▫ Proposed that electrons

move around the nucleus in certain paths or energy levels. Electrons can jump from

one level to another level but do not occupy the space between the energy levels.

I can recognize that all matter is made of atoms.I can identify the particles that make up an atom.

The Modern Atomic Theory• Erwin Schrodinger –

Austrian physicist (awarded Nobel Prize in 1933)

• Werner Heisenberg – German physicist (awarded Nobel Prize in 1932)▫ Electrons travel in

regions around the nucleus of an atom where they are likely to be found called electron clouds

I can recognize that all matter is made of atoms.I can identify the location of each particle in an atom.

Modern Atomic Theory (20th century)

Schrodinger, Heisenberg Electron clouds-regions electrons likely found

Bohr (1913)Energy levels-paths in which electrons travel

Rutherford (1911)Nucleus-central region of atom that has positive charge

Thomson (1897)Discovered electrons-negative particle Plum-pudding model

Dalton (1803)All substances made of atoms Atoms can join to make new substances

DemocritusAtom – smallest particle that cannot be divided


Objectives

• SPI 0807.9.1 Recognize that all matter consists of atoms.• SPI 0807.12.5 Determine the relationship among the mass

of objects, the distance between these objects, and the amount of gravitational attraction.

• I can:1. I can recognize that all matter is made of atoms.2. I can identify the parts of an atom.3. I can identify the charge and location of each particle in an

atom.4. Explain how an atom can be neutral and how the atom can

become charged.5. Explain how gravity is affected by the mass of an object

and the distance between objects.

The Atom

•Extremely small▫One penny contains 2 x 1022 atoms▫One Al atom has a diameter of 0.00000003

cm▫Al foil is 50,000 atoms thick


The Atom• Nucleus – small, dense, positively charged center of the

atom▫ Contains most of the atom’s mass1. Protons (p+)– positively charged particle in the

nucleus Mass of one proton is 1.7 x 10-24 g = 1 amu (atomic mass

unit)2. Neutrons (n0)– particles in the nucleus that has no

charge. Mass = 1 amu

• Electrons – negatively charged particles of an atom▫ Found outside the nucleus in electron clouds▫ Mass of one electron is almost zero▫ 1,800 electrons = mass of 1 proton

I can identify the parts of an atom.I can identify the charge and location of each particle in an atom.



The Atom

•# of protons = #of electrons▫The charges cancel out, so the atom has an

overall neutral charge•If protons ≠ electrons, then the atom

becomes charged▫Ion – charged particle▫Lose electron → lose negative → positive ion▫Gain electron → gain negative → negative

ion

Explain how an atom can be neutral and how the atom can become charged.

Forces in Atoms

1. Gravitational forces ▫ Acts on all objects all the time▫ Pulls objects toward one another▫ Depends on mass and distance between

particles Greater mass has greater gravitational pull Closer distance has greater gravitational

pull▫ Very small in atoms

I can explain how gravity is affected by the mass of an object and the distance between objects.

Forces in Atoms2. Electromagnetic Force

▫ Same charge repels▫ Opposite charges

attract▫ Protons and electrons

attract▫ Holds electrons around

the nucleus


Forces in Atoms

3. Strong force ▫ Holds protons together in the nucleus▫ Greater than EM force


Forces in Atoms

4. Weak force▫ Found in radioactive elements

(unstable atoms that spontaneously fall apart over time)

▫ Allows a neutron to change into a proton or electron


Objectives• SPI 0807.9.1 Recognize that all matter consists

of atoms.• SPI 0807.9.9 Use the periodic table to

determine the properties of an element.• I can:1. Identify the parts of an atom.2. Identify the charge and location of each

particle in an atom.3. Identify the atomic number, atomic mass,

number of protons, neutrons, and electrons in an atom using the periodic table.

Building Atoms1. Determine atomic number for the element

▫ Top number on periodic table Number of protons and electrons for that element

2. Determine atomic mass for the element▫ Bottom number (rounded) on periodic table

3. Subtract atomic # from atomic mass▫ Number of neutrons

4. Draw the atom with the correct number of protons and neutrons in the nucleus

5. Place electrons in electron clouds around the nucleus▫ Only 2 electrons go in the first energy level, only 8 in the

second, 18 in the third, 32 in the fourth, 50 in the fifth, 72 in the sixth

I can identify the atomic number, atomic mass, number of protons, neutrons, and electrons in an atom using the periodic table.

Carbon

1. Atomic number = 6▫ # of protons = # of electrons = 6

2. Atomic mass = 12.01 =123. Atomic mass – atomic # = # of neutrons

▫ 12 – 6 = 6 neutrons


Aluminum

1. Atomic number = 13▫ # of protons = # of electrons = 13

2. Atomic mass = 26.98154 =27▫ Atomic mass – atomic # = # of neutrons

3. 27 – 13 = 14 neutrons


Isotopes•Atoms that have a different number of

neutrons, but the same number of protons▫Isotopes are still the same element, because

they have the same number of protons The number of protons determine which

element you have If you change the # of protons, then the element

changes▫Isotopes have the same chemical properties

and most physical properties

2,670 known isotopes

38 isotopes of tin


Naming Isotopes

1. Write the name of the element2. Followed by a hyphen (-)3. Followed by the mass # of the isotope

•Hydrogen-1•Lithium-5•Cobalt-60•Gallium-71

I c an identify the atomic number, atomic mass, number of protons, neutrons, and electrons in an atom using the periodic table.

BoronBoron-10 Boron-11

• Atomic # = 5• #of protons =# of

electrons = 5• Mass number = 10• Mass # - atomic # = #

neutrons▫ 10-5 = 5 neutrons

• Atomic # = 5• #of protons =# of

electrons = 5• Mass number = 11• Mass # - atomic # = #

neutrons▫ 11-5 = 6 neutrons

I c an identify the atomic number, atomic mass, number of protons, neutrons, and electrons in an atom using the periodic table.

The Periodic TableChapter 11

Objectives• SPI 0807.9.9 Use the periodic table to determine the properties of an

element.

• I can:1. Explain how the periodic table was first arranged and how it is

arranged today.2. Identify each element as a metal, nonmetal, or metalloid using the

zigzag line as a reference.3. Identify an element by its chemical symbol.4. Identify the groups and periods of the periodic table.5. Describe how chemical properties of elements are similar in the

same group.6. Label each group by name (ex: alkali metals, halogens, noble gases,

etc.)7. Identify similar properties for each group.8. Explain which groups are likely to react together .

The Pattern• Dmitri Mendeleev, Russian chemist

▫Discovered pattern in 1896 (63 elements has been discovered by this time) Wrote the names and properties of each element on

cards and arranged the cards by properties, density, appearance, and melting point – no pattern

Arranged by increasing atomic mass – pattern appeared• Pattern was periodic – repeats at regular

intervals▫Mendeleev named his table the Periodic Table of

elements▫Mendeleev predicted properties of missing elements

not yet found

I can explain how the periodic table was first arranged and how it is arranged today.

GermaniumMendeleev’s prediction

Actual Properties

Atomic mass 70 72.6

Density 5.5 5.3

Appearance Dark gray metal Gray metal

Melting Point High melting point 937◦C


Changing the Arrangement

•Henry Moseley, British scientist▫1914 - Determined the atomic number for

each element▫Rearranged the PT by increasing atomic

number▫All elements follow periodic law – the

repeating chemical and physical properties of elements change periodically with the elements’ atomic numbers



Decoding the Periodic Table1. Metals, Nonmetals, Metalloids

a. Metals Left of zigzag line Few electrons in outer energy level Most are solid at RT Shiny, malleable, ductile, good conductors of heat and

electricityb. Nonmetals

Right of zigzag line Almost complete set of electrons in outer energy level Noble gases (group 18) have complete set of electrons Most are gases at RT Not shiny, not malleable, not ductile, poor conductors, brittle

c. Metalloids Along zigzag line Half of a complete set of electrons in outer energy level Semiconductors Properties of both metals and nonmetals

I can identify each element as a metal, nonmetal, or metalloid using the zigzag line as a reference.

I can identify each element as a metal, nonmetal, or metalloid using the zigzag line as a reference.

Decoding the Periodic Table2. Chemical Symbol

▫ Names come from scientists, places

Mendelevium, californium

▫ Symbols are the same worldwide

▫ Consists of one or two letters

First letter is ALWAYS capitalized

Second letter is ALWAYS lowercase

Newer elements have 3 letters

I can identify an element by its chemical symbol.




Decoding the Periodic Table3. Periods

▫ Horizontal rows of elements (left to right)▫ Follow periodic pattern across a period▫ Becomes less metallic as you go to the right

on the PT▫ Seven periods

4. Groups (Family)▫ Vertical columns of elements (top to

bottom)▫ Similar chemical and physical properties▫ Eighteen groups

I can identify the groups and periods of the periodic table.

Reading the Periodic Table1. What information is given in each square on the periodic table?

▫ AN, AM, symbol, name, state, protons, electrons2. How many elements are liquid at RT? Which ones?

▫ 2▫ Hg, Br

3. How many are gas at RT?▫ 11

4. How many are metals?▫ 88

5. How many are nonmetals?▫ 18

6. How many are metalloids?▫ 6

7. How many groups?▫ 18

8. How many periods?▫ 7

9. List elements whose symbols do not seem to come from their English names?

▫ Sn, Hg, Pb, Sb, W, K, Na10. What elements are in the same group as oxygen?

▫ S, Se, Te, Po

Grouping the Elements

•Properties are similar in groups•Atoms in each group have the same

number of electrons in their outer energy level▫Atoms will gain, lose, or share electrons

with other atoms to obtain a complete set of electrons in their outer energy level

▫These atoms will form compounds

I can describe how chemical properties of elements are similar in the same group.I can label each group by name (ex: alkali metals, halogens, noble gases, etc.)I can identify similar properties for each group.I can explain which groups are likely to react together

Group 1: Alkali Metals

•All metals•1 electron in outer energy level•Very reactive•Soft•Silver•Shiny •Low density


Group 2: Alkaline-Earth Metals•Metals•2 electrons in outer energy level•Very reactive but less than alkali metals•Silver•Low density but higher than alkali metals


Groups 3-12: Transition Metals•Metals•1 or 2 electrons in outer energy level•Less reactive than alkaline-earth metals•Shiny•Good conductors of thermal energy and

electric current•Higher densities and melting points than

elements in groups 1 and 2 (except mercury)



Lanthanides Actinides• Period 6• Shiny• reactive

• Period 7• Radioactive• Elements after 94

(plutonium) are made in laboratories


Group 13: Boron Group•One metalloid, 4 metals•3 electrons in OEL•Reactive•Solids at room temperature•Aluminum (Al) is the most abundant

element on Earth


Group 14: Carbon Group

•2 metals, one nonmetal, two metalloids•4 electrons in OEL•Solids at RT


Group 15: Nitrogen Group

•1 metals, 2 metalloids, 2 nonmetals•5 electrons in OEL•Solids at RT•Nitrogen makes up to 80% of air


Group 16: Oxygen Group

•1 metal, 1 metalloid, 3 nonmetals•6 electrons in OEL•All solids except oxygen (gas)•Reactive•Oxygen makes up about 20% of air


Group 17: Halogens

•Nonmetals•7 electrons in OEL (only need to gain 1

electron for complete outer level)•Very reactive•Poor conductors of electric current•React with alkali metals (group 1) to form salts


Group 18: Noble Gases

•Nonmetals•8 electrons in OEL (except helium which

has 2)•Complete set of electrons in OEL•Unreactive•Colorless, odorless gases at RT


Hydrogen

•1 electron in OEL•Reactive•Colorless, odorless gas•Low density•Explosive reactions with oxygen•Most abundant element in the

universe


The Atom and the Periodic Table Chapter 10 and Chapter 11.

Documents

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nobel prize

location of electrons

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electrons travel

smaller parts

proved daltons theory

nucleus tiny