Periodic Table Trends

Question 1

Define Electronegativity

Answer 1

Electronegativity is the ability of an atom to attract electrons. Electronegativity increases across the periodic table.

Question 2

What is changing as we go across and down the periodic table?

Answer 2

1. The number of protons (+) in the nucleus
2. The distance between nucleus and valence electrons
3. Shielding from inner electron shells

Question 3

Define Ionisation (IE)

Answer 3

Ionisation is the amount of energy required to remove one valence electron from a mole of atoms when they are in a gas state. Unit kJ mol-1

Question 4

Across a row (IE)…

Answer 4

Ionisation energy increases. This is due to the increasing electrostatic attraction across a row

Question 5

Down a group (IE)

Answer 5

Ionisation energy decreases. This is due to the decreasing electrostatic attraction down a group

Question 6

Define Atomic radius

Answer 6

Atomic radius is the measurement of the size of the atom. The distance between the nucleus and the outermost electrons. If an atom is bigger, it will have smaller electronegativity.

Question 7

Across a row (Atomic radius)

Answer 7

Atomic radius decreases. This is due to the increasing electrostatic attraction across a row, electrons are pulled in closer

Question 8

Down a group (Atomic radius)

Answer 8

Atomic radius increases. This is due to the decreasing electrostatic attraction down a group, electrons are not pulled in as close

Question 9

Define Ionic radius

Answer 9

Ionic radius is the measurement of the size of the ion. The distance between the nucleus and the outermost electrons.

Question 10

Positive ions (ie Metals)

Answer 10

• Lose electrons from their outer shell
• Therefore, fewer electron shells so the distance from the nucleus of the outer shell and shielding decreases
• A positive ion has a smaller radius than its atom

Question 11

Negative ions (ie Non-metals)

Answer 11

• Gain electrons onto their outer shell
• Therefore, increased repulsion between the increased number of electrons
• Energy shells and proton numbers stay the same
• A negative ion has a larger radius than its atom