Trends in the periodic table

Question 1

atomic radius (trends)

Answer 1

1. Decreases across period
   - no screening effect
   - increase in charge
2. Increases down a group
   - increase in screening effect
   - extra energy level(s)

Question 2

1st ionization energy

Answer 2

the minimum energy required to completely remove the most loosely bond electron from a neutral gaseous atom in a ground state

Question 3

1st ionization energy (trends)

Answer 3

1. Increase across a period
   - increase in nuclear charge
   - decrease in atomic radius
2. Decrease down a group
   - increase in screening effect
   - increase in atomic radius
   (Exceptions; Be, N, Mg, P
   - due to Hund’s rule and increased stability)

Question 4

2nd ionization energy

Answer 4

the energy required to completely remove the most loosely bound electron from an ion with one positive charge in its gaseous state

Question 5

Electronegativity

Answer 5

a measure of the relative attraction atoms in a molecule have for the shared pair of electrons in a covalent bond