Trends in the periodic table

Question 1

What is atomic radius

Answer 1

measurement of the size of an atom
distance between the nucleus and valence electrons

Question 2

Atomic radius down a group (inc vs dc)

Answer 2

• core charge stays the same (protons inc but so does the number of shielding electrons)
• number of electron shells inc
• therefore atomic radius increases down a group

Question 3

Atomic radius across a period

Answer 3

• number of electron shells stays the same
• core charge increases (pulling electrons in)
• atomic radius decreases across a period

Question 4

Core charge

Answer 4

measure of attractive force felt by valence electrons towards the nucleus
number of protons - shielding electrons

Question 5

Core charge down a group

Answer 5

stays relatively constant
although protons increase, so do shielding electrons

Question 6

Core charge across a period

Answer 6

increases
shielding electrons is the same, but protons increase

Question 7

Ionisation energy

Answer 7

energy required to remove an electron from a neutral ion

Question 8

First ionisation energy

Answer 8

energy required to remove the first valence electron from a neutral ion

Question 9

Ionisation energy down a group

Answer 9

• since atomic radius increases
• but core charge stays constant
• there is a weaker electrostatic force
• easier to remove
• therefore lower ionisation energy

Question 10

ionisation energy across a period

Answer 10

• atomic radius decreases
• core charge increases
• stronger electrostatic attraction
• harder to remove
• therefore, higher ionisation energy

Question 11

electronegativity

Answer 11

ability of an atom in a molecule to attract electrons in a covalent bond

Question 12

electronegativity down a group

Answer 12

• decreases
• atomic radius increases

Question 13

electronegativity across a period

Answer 13

• increases
• atomic radius decreases
• and core charge increases