Chem Notes Ch 2

Question 1

Group

Answer 1

Elements that occupy the same column and have the same number of valance electrons.

Question 2

Period

Answer 2

Elements that occupy the same row and have the same number of electron shells

Question 3

Group 1 Elements (excluding hydrogen)

Answer 3

Alkali Metals

Question 4

Group 2 Elements

Answer 4

Alkaline Earth Metals

Question 5

Groups 3-12 Elements:

Answer 5

Transition Metals

Question 6

Groups 13-17 Elements

Answer 6

Metalloids, which have a combination of both metallic and non-metallic characteristics.

Question 7

Group 17 Elements

Answer 7

Halogens

Question 8

Group 18 Elements

Answer 8

Noble Gases

Question 9

Period 6 elements

Answer 9

Lanthanides

Question 10

Period 7 elements

Answer 10

Actinides

Question 11

Diatomic atoms

Answer 11

Hydrogen, Nitrogen, Fluorine,

Oxygen, Iodine, Chlorine, and Bromine. Have No Fear Of Ice Cold Beer

Question 12

Metallic character on periodic table trend

Answer 12

Increases going from right to left across a period and increases going down a group

Question 13

Properties of metals

Answer 13

Malleable, lustrous, good conductors of electricity/heat, forms basic oxides, lose electrons to form cations, usually solid at room temperature with exception of Hg liquid, high melting point, high boiling point

Question 14

Properties of non-metals

Answer 14

Brittle, dull, poor conductors of electricity/heat, form of acidic oxides, gain electrons to form anions, gas or solid at room temperature with exception of Br liquid, low melting point, low boiling point

Question 15

Atomic radius definition

Answer 15

Half the distance between the nuclei of two identical atoms bonded together

Question 16

Atomic radius trend

Answer 16

Decreases from left to right across a period and increases going down a group.

Question 17

Effective nuclear charge (Zeff) definition

Answer 17

Nuclear charge experienced by an electron in an atom with multiple electrons. This charge is assigned due to a shielding
effect of electrons preventing electrons in higher orbitals from experiencing a strong attraction to the nucleus. Explains why valence electrons are more easily removed.

Zeff = Number of protons - Number of shielding electrons

Question 18

Effective nuclear charge (Zeff) trend

Answer 18

Increases across a period from left to right and decreases going down a group. Across a period, numbers of protons increase with no increase in shielding effect, which results in electrons being pulled closer to the nucleus due to a
stronger attraction. Going down a group, more shielding causes Zeff to decrease.

Question 19

When a neutral atom loses an electron

Answer 19

Becomes a cation. Radius will decrease due to an increase in Zeff, causing increase in protons pulling the electrons closer to the nucleus.

Metals form cations, resulting in their ionic radius to be less than their atomic radius.

Question 20

When a neutral atom gains an electron

Answer 20

Becomes an anion. Radius will increase due to a decrease in Zeff, causing a decrease in protons pulling the electrons to the nucleus.

Non-metals form anions, resulting in their ionic radius to be greater than their atomic radius.

Question 21

Isoelectronic Series definition

Answer 21

Atoms that have the same electron configuration, but differing numbers of protons. The most positively charged atom will have the smallest radius

Question 22

Ionization energy definition

Answer 22

The energy needed to remove an electron from an atom

Question 23

Ionization energy Trend

Answer 23

Increases going from left to right across a period and

decreases down a group, because of Zeff trend.

Question 24

Multiple Ionization Energies

Answer 24

The first ionization energy is the energy required to
remove the outermost electron. Following removal of the first electron, elements can have second, third, fourth, etc. ionization energies. These values are always larger than
the first ionization energy because subsequent electrons are more difficult to remove.

Question 25

2 exceptions to the rules for ionization energy

Answer 25

1. Alkaline earth metals have greater ionization energy than group 13 elements because alkaline earth metals have completely filled orbitals
2. Group 15 elements have greater ionization energy than
   group 16 elements. Group 15 elements have half-filled orbitals

Question 26

Electron Affinity definition

Answer 26

Amount of energy released when an electron is added to an atom

Question 27

Electron Affinity trend

Answer 27

Increases from left to right across a period and decreases down a group. Going across a period, greater nuclear attraction between protons and electrons creates a stronger affinity for electrons. Going down a group, the attraction of an electron to the nucleus decreases due to shielding.

Note: Similar to ionization energy, the trend for electron affinity is a general trend and may not apply to all elements in the periodic table. For example, although phosphorous is to the right of silicon, phosphorous has a half-filled subshell electron configuration. Silicon has a
greater affinity for an electron than phosphorous because accepting an electron will give it the half-filled subshell configuration.

Question 28

Electronegativity definition

Answer 28

Ability of an atom to attract electrons in a bond. The higher the electronegativity of an atom, the greater ability to attract an electron pair

Question 29

Electronegativity trend

Answer 29

increases going from left to right across a period and decreases down a group. The most electronegative element is fluorine

Noble gases are an exception to this trend as they have full valence shells and no electronegativity value.