Periodicity

Question 1

Meaning of periodicity

Answer 1

The occurrence of patterns in the periodic table

Question 2

periodicity across a row

Answer 2

The atomic number increases for each successive element and the number of energy levels is the same

Question 3

periodicity down a group

Answer 3

An occupied electron energy level is gained

Question 4

down a group atomic size/covalent radius

Answer 4

Increases

Question 5

across a row atomic size/covalent radius

Answer 5

Decreases

Question 6

What is covalent radius

Answer 6

half of the distance between the nuclei of two bonded atoms of an element

Question 7

Why is there is no covalent radius data for the noble gases

Answer 7

because they are monatomic elements

Question 8

Why does covalent radius increase when going down a group

Answer 8

elements within the same group have one more occupied energy level as you go down the group

Question 9

Why does covalent radius decrease when going across a period

Answer 9

Atoms within the same period have an increased proton in the nucleus going down each element. The increased positive charge on the nucleus increases the attraction for the electron in the outer energy level and they are pulled closer to the nucleus, making atoms smaller

Question 10

First ionisation energy

Answer 10

the energy required to remove one electron from each atom of one mole of gaseous atoms

Question 11

Second ionisation energy

Answer 11

the energy required to remove one electron from each singly positive ion of one mole of the gaseous ions

Question 12

What state symbol is essential in ionisation

Answer 12

g

Question 13

Is ionistion endothermic or exothermic

Answer 13

Endothermic

Question 14

Ionisation down a group

Answer 14

decrease

Question 15

Ionisation across a period

Answer 15

increase

Question 16

Cause of Ionisation down a group

Answer 16

One more occupied energy level

Question 17

Cause Ionisation across a period

Answer 17

Increased number of protons

Question 18

Explained Cause of Ionisation down a group

Answer 18

The electron removed is further from the nucleus so the electron is more shielded. The weaker electrostatic attraction makes it easier to remove the electron.

Question 19

Explained Cause Ionisation across a period

Answer 19

The increased positive charge increases attraction so it requires more energy to remove the electrons.

Question 20

Why are Second and third ionisation energies larger than the first

Answer 20

the extra positive nuclear charge(s) has greater electrostatic attraction for the outer electrons and therefore more energy is required to remove the electrons.

Question 21

What is Electronegativity

Answer 21

Electronegativity is a measure of the attraction an atom involved in a bond has for the electrons of the bond.

Question 22

What does higher electronegativity mean

Answer 22

The higher electronegativity, the more strongly the nucleus attracts electrons towards it.

Question 23

electronegativity down a group cause

Answer 23

One more occupied energy level

Question 24

electronegativity across a period cause

Answer 24

Increased positive charge on the nucleus

Question 25

Electronegativity down a group

Answer 25

decrease

Question 26

Electronegativity across a period

Answer 26

increase

Question 27

Electronegativity down a group explained

Answer 27

The electron removed is further from the nucleus so the electron is more shielded. This means there is weaker electrostatic attraction

Question 28

Electronegativity across a period explained

Answer 28

The nucleus has a stronger electrostatic attraction for the electrons.

Question 29

Why breaking full shells takes more energy

Answer 29

-Electrons are closer to the nucleus
-Electrons are less screened from the nucleus as there are fewer inner electron energy levels
Therefore there is more electrostatic attraction