Unit 1 - Trends in the Periodic Table

Question 1

covalent radius definition

Answer 1

half the distance between the nuclei of two bonded atoms

Question 2

first ionisation energy definition

Answer 2

energy required to remove one mole of electrons from one mole of gaseous atoms

Question 3

electronegativity definition

Answer 3

a measure of the attraction an atom of an element has for bonding electrons

Question 4

covalent radius across period

Answer 4

decreases:

increasing nuclear charge (more protons) pulls electrons closer to the nucleus

Question 5

covalent radius down group

Answer 5

increases:

increasing number of electron shells makes the atoms bigger

Question 6

first ionisation across period

Answer 6

increases:

smaller radius means outer electrons are more strongly held so more energy is required to remove electrons

Question 7

first ionisation down group

Answer 7

decreases:
increased shielding (more electron shells) means outer electrons are less strongly held

Question 8

electronegativity across period

Answer 8

increases:
atoms have increasing nuclear charge so have a smaller covalent radius meaning the nucleus attracts the bonding electrons more strongly

Question 9

electronegativity down group

Answer 9

decreases:
larger covalent radius due to extra electron shells meaning bonding electrons are further from the nucleus, so due to the shielding effect, atoms have less attraction for bonding electrons