Periodic Trends

Question 1

What is Atomic Size

Answer 1

A measure of how large individual atoms/ions are

Question 2

Atomic Size across a period

Answer 2

it decreases because as you go across the period the nuclear charge of the atom increases pulling electrons more tightly therefore the atom is smaller

Question 3

Atomic Size Down a Group

Answer 3

it decreases because as you go down group electrons are further from the nucleus as there are more electron shells and the inner electron shells also shield the extra electron shells from the pool of the nucleus so they are less tightly pulled in

Question 4

Ionisation Energy

Answer 4

The energy required to remove one mole of electrons from one mole of gaseous atoms/ions

Question 5

Ionisation energy across a period

Answer 5

it increases because as you go across the period nuclear charge of the atom increases putting the electrons in more tightly so it’s more difficult to remove one mole of electrons

Question 6

Ionisation Trend down a group

Answer 6

as you go down the group electrons are further from the nucleus and the inner electron shells also shield the outer electron shells from the pool of the nucleus so removing one mole of electrons is easier

Question 7

Electronegativity

Answer 7

A measure of the attraction of an atom has for a shared pair of electrons in a covalent bond

Question 8

Electronegativity Across A Period

Answer 8

it’s increases because as you go across the period the nuclear charge of the atom increases pulling electrons in more tightly therefore they have a larger attraction

Question 9

Electronegativity Down a Group

Answer 9

decreases because as you go down the group the electrons are further from the nucleus and the inner electron shells shield outer electron shells from the pool of the nucleus so shared pairs are more easily removed and there is less attraction

Question 10

Melting Points and Boiling Points across a period

Answer 10

The melting and points depends on the strength of forces which exist between the particles which make up a substance. Across a period from left to right the melting and boiling point increases until group 4, after this it plummets. This is due to strong attractions between the atoms in group 1 to 4 and after this there is a decrease in the forces of attraction between the atoms.

Question 11

Melting Points and Boiling Points down a group

Answer 11

The melting and boiling points of the group 1 elements decrease understanding the group this is due to a decrease in the forces of attraction between the atoms, the opposite happens to the halogens