Module 7: Periodic Variations

Question 1

Defined as one-half the distance between the nuclei of two identical atoms when they are joined by a covalent bond

Answer 1

Covalent Radius

Question 2

Trend in Covalent Raidus

Answer 2

across a period it decreases

down a group it increases

Question 3

This is the pull exerted on a specific electron by the nucleus taking into account any electron-electron repulsion

Answer 3

Zeff (effective nuclear charge)

Question 4

formula for Zeff

Answer 4

Z (atomic number) - shielding (core electrons)

Question 5

trend for Zeff

Answer 5

across a period it increases

Question 6

determined by the probability of another electron being between the electron of interest and the nucleus as well as by the electron-electron repulsions the electron of interest encounters

Answer 6

Shielding

Question 7

the measure used to describe the size of an ion

Answer 7

Ionic radius

Question 8

Trend in Ionic Radii

Answer 8

across a period it decreases

down a group it increases

Question 9

Is a cation always smaller than its parent atom?

Answer 9

Yes

Question 10

What happens to Zeff as electrons are removed

Answer 10

Increases

Question 11

Cations with larger charges are bigger that cations with smaller charges

Answer 11

False

Question 12

What happens to Zeff as electrons are added

Answer 12

Decreases

Question 13

Is an anion always smaller than its parent atom?

Answer 13

No

Question 14

atoms and ions with the same electron configurations

Answer 14

Isoelectronic

Question 15

For isoelectronic atoms and ions, what determines their size?

Answer 15

the number of protons

Question 16

What happens to the atomic radius as the nuclear charge increases in a series of isoelectronic atoms and ions?

Answer 16

Decreases

Question 17

This is the amount of energy required to remove the most loosely bound electron from a gaseous atom in its ground state

Answer 17

Ionization Energy

Question 18

Trend in Ionization Energy

Answer 18

across a period it increases

down a group it decreases

Question 19

What type of electron is removed when there is a sudden jump in Ionization Energies?

Answer 19

Core Electron

Question 20

the energy change for the process of adding an electron to a gaseous atom

Answer 20

Electron Affinity

Question 21

What kind of energy process does negative electron affinity means?

Answer 21

Exothermic (energy is released)

Question 22

the more negative the EA is the greater its Electron Affinity?

Answer 22

Yes

Question 23

Trend in Electron Affinity

Answer 23

across a period it increases

down a group it decreases

Question 24

rows

Answer 24

Periods

Question 25

it will tell you the highest value of n

Answer 25

Periods

Question 26

it describes the occupied main energy levels

Answer 26

Periods

Question 27

it describes the location of the differentiating electron

Answer 27

Group/Family

Question 28

columns

Answer 28

Group/Family

Question 29

The electron needed in going from one element to the next in Aufbau Principle

Answer 29

Differentiating Electron

Question 30

last electron added in the electron configuration

Answer 30

Differentiating Electron

Question 31

2 ways of assigning groups

Answer 31

US Convention

IUPAC

Question 32

In US Convention, how to assign Group A and number?

Answer 32

location of differentiating electron is in s or p

then group number is the number of valence electron

Question 33

In US Convention, how to assign Group B and number?

Answer 33

location of differentiating electron is in d or f

then group number is number of [ns + (n-1)d] electrons

Question 34

In IUPAC way of assigning group, what is group number if element is in s or p block?

Answer 34

tens digit is 1

unit digit is number of valence electrons

Question 35

In IUPAC way of assigning group, what is group number if element is in d block?

Answer 35

group number is equal to number of [ns + (n-1)d] electrons

Question 36

Trend in atomic size

Answer 36

across a period it decreases

down a group it increases

Question 37

Trend in metallic property

Answer 37

across a period it decreases

down a group it increases

Question 38

What happen to atomic size and Zeff when valence electrons increases?

Answer 38

atomic size decreases

Zeff increases

Question 39

Trend in electronegativity

Answer 39

across a period increases

down a group decreases

Question 40

elements with the greatest electronegativity

Answer 40

Fluorine
Oxygen
Nitrogen