Chapter 7:Trends In The Periodic Table

Question 1

Atomic radius

Answer 1

Of an atom is defined as half the distance between the nuclei of two atoms of the same element that are joined together by a single covalent bond

Question 2

First Ionisation Energy

Answer 2

Of an atom is the minimum energy required to completely remove the most loosely bound electron from a neutral gaseous atom in its ground state

Question 3

Second Ionisation Energy

Answer 3

Is the energy required to remove an electron from an ion with one positive charge in the gaseous state
X+ = X2+ e-

Question 4

When do atomic radius values increase?

Answer 4

Down any one group in the periodic table because the electrons are going into a new energy level that is further from the nucleus and there is an increase in the screening effect by inner electrons.

Question 5

When do atomic radius values decrease?

Answer 5

From left to right across a period because of increasing effective nuclear charge and no increase in the screening effect.

Question 6

When do first ionisation values increase?

Answer 6

Along periods because of increasing effective nuclear charge and decreasing atomic radius

Question 7

When do first ionisation values decrease?

Answer 7

Down the group because of increasing atomic radius and an increase in the screening effect of inner electrons.

Question 8

Why do elements with filled and half-filled sublevels have higher energy ionisation energies than expected?

Answer 8

They have extra stability

Question 9

When do electronegativity values increase?

Answer 9

Along the periods because of increasing effetive nuclear charge and decreasing atomic radius

Question 10

When do electronegativity values decrease?

Answer 10

Down a group because of increasing atomic radius and an increase in the screening effect of inner electrons

Question 11

What trends are in Group 1 (Alkali Metals)?

Answer 11

Very reactive(low first ionisation energy)
Reactivity increases down the group.

Question 12

How do Alkali Metals react in water?

Answer 12

Creates hydroxide and hydrogen gas
React vigorously down the group
2Na+2H2O=2NaOH+H2

Question 13

How do Alkali Metals react in acid?

Answer 13

Release hydrogen

Can lead to an explosion

Question 14

What trends are in Group 7 (Halogens)?

Answer 14

Electronegativity decrease down the group
Very reactive(high electronegativity)