Periodicity

Question 1

In metallic bonding delocalised outer electrons produces…

Answer 1

An electrostatic force of attraction between the positive metal ions and the negative delocalised electrons.

Question 2

What is a covalent bond ?

Answer 2

A shared pair of electrons electrostatically attracted to the positive nuclei of two non-metal atoms.

Question 3

How do the atoms achieve a stable outer electron arrangement (a noble gas arrangement) ?

Answer 3

By sharing electrons.

Question 4

Most of the discrete covalent molecules are…

Answer 4

Diatomic

Question 5

There are also some larger covalent molecular elements:

Answer 5

Phosphorus (P4)
Sulfur (S8)
Fullerenes (C60)

Question 6

What are covalent networks ?

Answer 6

Large, rigid three dimensional arrangements of atoms held together by strong covalent bonds.

Question 7

Why do covalent networks have high melting points ?

Answer 7

Because they only contain strong covalent bonds.

Question 8

Example of covalent network

Answer 8

Carbon in the forms of diamond and graphite.

Question 9

Which elements exist as single unattached particles ?

Answer 9

Group 0 elements (noble gases) including helium, neon and argon.

Question 10

Noble gases are…

Answer 10

Stable atoms

Question 11

Noble gases do not usually…

Answer 11

Form molecules with other atoms.

Question 12

Monatomic elements have…

Answer 12

Low MPts and BPts as weak forces of attraction between the atoms.

Question 13

What is the first ionisation energy ?

Answer 13

The energy involved in removing one mole of electrons from one mole of atoms in the gaseous state.

Question 14

The second ionisation energy is…

Answer 14

The energy required to remove a second mole of electrons.

Question 15

The third ionisation energy shows a massive increase because…

Answer 15

It requires an electron to be removed from Magnesium’s second energy level.

Question 16

As you go across the periodic table the ionisation energy…

Answer 16

Increases due to an increase in nuclear charge having a greater pull on the electrons and therefore more energy is required to remove electrons.

Question 17

As you go down a group in the periodic table the ionisation energy…

Answer 17

Decreases due to the screening effect of the outer electrons from the nucleus and so the attraction is weaker and they are removed more easily.

Question 18

As you go across the periodic table the covalent radius…

Answer 18

Decreases due to there being more electrons in the outer energy level and more protons in the nucleus which results in an increased nuclear charge

Question 19

As you go down a group in the periodic table the covalent radius…

Answer 19

Increases due to the screening effect of the filled inner electron levels, these electron screen the outer electrons from the nuclear charge.

Question 20

What is electronegativity ?

Answer 20

A measure of an atom’s attraction for the electrons in a bond.

Question 21

As you go across the periodic table electronegativity…

Answer 21

Increases due to the atoms having a greater nuclear charge and a smaller covalent radius which allows the nucleus to attract bonding electrons more strongly.

Question 22

As you go down a group in the periodic table electronegativity…

Answer 22

Decreases due to extra energy levels and increased covalent radius which keep the bonding electrons further away from the nucleus.