PSC 4010

PSC 4010

PSC 4010Nuclear Technology: A matter of Energy

PSC 4010: Chapter 3Goals:

_ SWBAT locate the different families and groups of elements found in the modern Periodic Table

_SWBAT use information found or deducted from the modern Periodic Table about any of the first twenty elements

_SWBAT compare the atomic structure of the isotopes of an element

_SWBAT calculate the atomic mass of an element, given the relative abundance of its isotopes

PSC 4010: Chapter 3Classification of elements:

Dalton

_Made a list of 60 known elements

_From lightest (Hydrogen) to heaviest

Mendeleyev

_Created first Periodic Table (page 3.6)_Organized elements according to Atomic Mass_Periodic: Columns of element with similar properties_Predicted existence of elements according to observed periodicity (blank spaces in table)

PSC 4010: Chapter 3Symbols:

You must know the name of the first 20 elements of the Periodic Table (plus a couple of very common metals)Some elements are represented by a capital letter, others by a combination of two (capital and lower capital) Examples: O (Oxygen), Fe (Iron)

PSC 4010: Chapter 3Modern Periodical Table

90 natural elements19 artificial elementsElements are organized according to their atomic numberHorizontal rows represent Periods or Energy LevelsVertical rows represent Groups or Families of elements, with similar chemical properties

PSC 4010: Chapter 3Modern Periodical Table

Black elements are solids Blue elements are liquids [only two: Mercury (Hg) and Bromine (Br)]Red ones are gases [eleven: Hydrogen (H), Nitrogen (N), Oxygen (O), Fluorine (F), Chlorine (Cl), Helium (He), Neon (Ne), Argon (Ar), Krypton (Kr), Xenon (Xe) and Radon (Rn)]PSC 4010: Chapter 3Atomic numbers

PSC 4010: Chapter 3Periods

Period IH: 1eHe:2e

Period IILi: 2e, 1eBe:2e, 2eN: 2e, 5ePeriod IIINa:2e, 8e, 1eP: 2e, 8e, 5eCl: 2e, 8e, 7e

Period IH: 1eHe:2e

Period IILi: 2e, 1eBe:2e, 2eN: 2e, 5ePeriod IIINa:2e, 8e, 1eP: 2e, 8e, 5eCl: 2e, 8e, 7eThe number of the period tells you the amount of energy levels for electrons to surround the nucleusPSC 4010: Chapter 3Groups (Families)

Group ILi:2e, 1eNa: 2e, 8e, 1eK: 2e, 8e, 8e, 1eGroup IIBe:2e, 2eMg: 2e, 8e, 2eCa: 2e, 8e, 8e, 2eGroup V

N:2e, 5eP: 2e, 8e, 5eGroup ILi:2e, 1eNa: 2e, 8e, 1eK: 2e, 8e, 8e, 1eGroup IIBe:2e, 2eMg: 2e, 8e, 2eCa: 2e, 8e, 8e, 2eGroup V

N:2e, 5eP: 2e, 8e, 5eThe number of the group (family) tells you the amount of electrons in the last shellPSC 4010: Chapter 3

PSC 4010: Chapter 3Metals:

On the left of dark staircased-type line (except Hydrogen)Metallic lusterConduct electricity and heatNon-metals:

On the right of dark staircased-type line (also Hydrogen)Do not have shiny lusterDo not conduct electricity or heatPSC 4010: Chapter 3Group IAAlkali metalsOne electron in outermost shell Very soft to touchExtremely reactive with water (stored swimming in oil, to avoid reaction with airs humidity)

PSC 4010: Chapter 3

PSC 4010: Chapter 3Group IIA

Alkaline-Earth metalsTwo electrons in outermost shell Less soft to touchLess reactive with water

PSC 4010: Chapter 3Transition Metals

Heavy metals between groups IIA and IIIA

PSC 4010: Chapter 3Lantanides

15 heavy metals from atomic number 57 to 71They have very similar propertiesName comes from Lanthanum, the first of them

PSC 4010: Chapter 3Actinides

15 heavy metals from atomic number 89 to 103They have very similar propertiesName comes from Actinium, the first of themThey are radioactive (unstable, nuclei break into smaller atoms)

PSC 4010: Chapter 3Group VIIA

HalogensThey have seven electrons in their outermost shellThey are very reactiveNever to be found alone (if not attached to another element, attached to themselves in diatomic molecules, e.g. Cl2 , F2 , etc.)

PSC 4010: Chapter 3Group VIIIA

Noble GasesThey have eight electrons in their outermost shellThey are very inertDo not react with anybody, and are considered rare gases for they account for only 1% of gases in atmosphere

PSC 4010: Chapter 3Hydrogen

One of a kindLightest and most abundant elementNon-metal (gaseous)

PSC 4010: Chapter 2Practice Exercises:Page 3.8 Ex 3.4 & 3.5Page 3.23 3.24 Ex 3.9 3.11Page 2.13 Ex 2.5

PSC 4010: Chapter 3IsotopesAtoms that have the same number of protons (and electrons), but different number of neutrons.

Isotopes have the same atomic number, but different atomic masses (and mass number)

Mass number is the atomic mass rounded to its closest integer. It represents the number of protons plus the number of neutrons

(#neutrons = mass number atomic number)PSC 4010: Chapter 3Isotopes notation

The higher the number of neutrons in an isotope, the lower its stability

PSC 4010: Chapter 3The atomic mass of isotopes of the same element is the result of the mixture of these isotopes in different proportions

The proportion of an isotope is expressed as a percentage, and it is called relative abundance (table on page 3.28)

Therefore, in order to calculate the real atomic mass of any element, you have to multiply the mass number of each isotope by their relative abundance percentage, and add them together.

PSC 4010: Chapter 3Example:

Knowing that there is a 98.99% of C-12 in nature, a 1.11% of C-13, and traces of C-14, calculate the atomic mass of Carbon (C):

= (12 * 98.99/100) + (13 * 1.11/100) + 14 (0/100)= 11.8668 amu + 0.1443 amu = 12.0111 amu

PSC 4010: Chapter 3Need another example of calculations?!(Table 3.1, page 3.28, Nitrogen)

Knowing that there is a 99.64% of N-14 in nature, and a 0.37% of N-15, calculate the atomic mass of Nitrogen (N):

= (14 * 99.64/100) + (15 * 0.37/100) = 13.9496 amu + 0.0555 amu = 14.0051 amuPSC 4010: Chapter 3What have we learned so far?Modern Periodic Table organized in increasing number of atomic number (or # protons or # electrons)Each groups number is equal to the number of electrons in outermost shellEach periods number is equal to the number of energy levels (orbits) of electronsMetals are found on the left of dark stair cased-type line (except Hydrogen)Non-metals are found on the right of dark stair cased-type line (also Hydrogen)

Group IA: Alkali metalsGroup IIA: Alkaline-Earth metalsGroup VIIA: HalogensGroup VIIIA: Noble Gases

PSC 4010: Chapter 3What have we learned about isotopes?Isotopes are atoms of the same element, with same atomic number, but different atomic massSame atomic number, therefore, same number of protons (and electrons)Mass number is the closest integer to which atomic mass (a decimal) is rounded up toMass number = Atomic number (# protons) + # neutrons Atomic mass = (mass number)I1 * (relative abundance) I1 + (mass number)I2 * (relative abundance) I2 + ... + (mass number)In * (relative abundance) In + PSC 4010: Chapter 2Practice Exercises:

Page 3.29 3.30 Ex 3.13 3.16PSC 4010: Chapter 2Practice Exercises for Chapter 3:

Page 3.34 3.38 Ex 3.17 3.34