3.1

Question 1

what is the trend in properties repeated across a period.

Answer 1

Periodicity

Question 2

energy levels in orbitals

Answer 2

within the sub shell energies increase with d having the most

Question 3

group 2 elements (properties)

Answer 3

Have reasonably high melting and boiling points.

All light metals with low density.

Form colourless (white) compounds

Question 4

Reactions of group two elements and oxygen

Answer 4

The group two elements react vigorously with oxygen (redox reaction)

Question 5

Reaction of group two and water

Answer 5

All group two elements apart from beryllium react to form hydroxides.

The general formula is M(OH)2

Hydrogen gas is formed and moving down the group they react more.

Question 6

solubility down group 2

Answer 6

increases

Question 7

alkalinity down group 2

Answer 7

increases

Question 8

calcium hydroxide uses

Answer 8

used by farmers and gardeners to reduce the acidity in soil

Question 9

use for magnesium hydroxide

Answer 9

neutralising the excess acid and produces salt and water

Question 10

The halogen properties

Answer 10

Have low melting and boiling points

Exist as diatomic molecules

Question 11

Trend in boiling points of group 7

Answer 11

The boiling point increases and it goes from gas to liquid to solid.

this is due to the fact that each element has an extra shell of electrons which leads to more temporary dipole dipole bonds

Question 12

The reactivity and oxidising power down group 7.

Answer 12

This decreases due to:

the atomic radius increasing (nuclear pull is further away from incoming electrons)

the shielding increases

Question 13

what are the three things effecting ionisation energies.

Answer 13

Nuclear charge- the more protons there are in the nucleus, the more positively charged the nucleus is and the stronger the attraction for the electrons.

Atomic radius- Attraction falls off very rapidly with distance. An electron close to the nucleus will be much more strongly attracted to one further away.

Shielding- As the number of electrons between the outer electrons and the nucleus increases the outer electrons feel less attraction towards the nuclear charge-.

Question 14

ionisation energy trend down a group

Answer 14

The ionisation energies fall. (larger atomic radius, more shielding) this counteracts the increased nuclear charge- increasing

Question 15

ionisation energy across a period(general trend)

Answer 15

As you move across a period the general trend is that they increase (due to more nuclear charge and smaller atomic radius)

Question 16

ionisation energy between group 2 and 3

Answer 16

There is a slight dip as the outer electron in group 3 is in a P orbital. this provides slightly more shielding and a bigger atomic radius.

Question 17

ionisation energy between 5 and 6

Answer 17

There is a slight decrease due to there being 4 electrons in the p orbital so some repulsion occurs.

Question 18

The first ionisation energy definition.

Answer 18

The first ionisation energy of an element is the energy required to remove one electron from each atom in one mole of the gaseous element to form one mole of 1+ ions.

Question 19

What is metallic bonding?

Answer 19

Strong electrostatic attraction between cations (positive ions) and delocalised electrons.

Question 20

Properties of giant metallic lattices

Answer 20

High melting and Bp’s.

Good electrical conductors

Malleable and ductile as the delocalised electrons can move in the structure.

Question 21

What happens as you move across period 2 and 3?

Answer 21

The elements change from metal to non metal.

Solids to gases.

giant metallic, giant covalent and then to simple molecular.