1.1 Periodicity

Question 1

1.1a- Element Arrangement

What direction are
* Periods
* Groups

Answer 1

• Horizontal
• Vertical

Question 2

1.1b- Atomic Size

How is Atomic Size affected by crossing a period?

Answer 2

On crossing period, from left to right, atomic number increases ∴ more protons are added to the nucleus. The electrons in the outer energy levels are ∴ attracted more strongly to the +positive nucleus, making the atom smaller

Question 3

1.1b- Atomic size

How is Atomic Size affected by descending a group?

Answer 3

As you move down a group the number of occupied electron energy levels increases, making atoms bigger

Question 4

1.2c- Ionization energy

Define: “Ionization energy”

Answer 4

The energy required to remove 1 mole of electrons from 1 mole of atoms in the gaseous state

Question 5

1.1c- Ionization energy

Where can ionization energies be found?

Answer 5

Data booklet page 12

Question 6

1.1c- Ionization energy

How is an element ionized?

Answer 6

X(g)→ X+(g) +e-

Question 7

1.1c- Ionization energy

What must you write when doing ionization equations?

Answer 7

• State symbols!
• (g)

Question 8

1.1c- Ionization energy

What causes large jumps in consecutive ionization energies for an element?

Answer 8

An electron being taken from a full electron shell vs a partially filled one

Question 9

1.1c- Ionization energy

How is inization energy affected by crossing a period?

Answer 9

• More protons are added to the nuclei of the atoms.
• This results in an increase in nuclear charge.
• The electrons in the outer energy levels will be more tightly held, & more energy is required to remove them

Question 10

1.1c- Ionization energy

How does going down a group decrease ionization energy

Answer 10

• Electron being removed comes from the outer electron level which is increasingly distant due to increasing atomic size (extra energy levels) ∴ the attraction between positive nucleus & negative electrons diminishes.
• Electrons in the inner energy levels will shield those in the outer energy level from the full nuclear charge & so lessen the attraction between nucleus & electron being removed

Question 11

1.1d- Electronegativity

Define: “Electronegativity”

Answer 11

Measure of the attraction an atom involved in a bond has for the electrons in that bond

Question 12

1.1d- Electronegativity

Effect of crossing a period on electronegativity

Answer 12

Electronegativity increases. This is caused by an increase in nuclear charge as you move accross a period from left to right i.e it has a greater attraction for the bonding electrons

Question 13

1.1d- Electronegativity

Effect of descending a group on Electronegativity

Answer 13

• Electronegativity decreases.
• This caused by the addition of another energy level of electrons as you go down a grouo which increases the distance between the bonded electrons & nucleus.
• The** increasing number of inner electrons** also shield the bonding electrons from the nuclear charge.