Section 1.7 The Arrangement of Electrons in Atoms

Question 1

How are electrons arranged around the nucleus?

Answer 1

In equal distance from each other in energy shells, which represent different energy levels

Question 2

How many electrons can each energy shell hold?

Answer 2

The first and lowest energy level can only hold up to 2 electrons

The rest of the energy shells can hold up to 8 electrons

(Energy shells are added only if the last one is filled up to 2 or 8)

Question 3

What is the electronic structure of Boron?

Answer 3

2, 3

Question 4

What is the electronic structure of Calcium?

Answer 4

2, 8, 8, 2

Question 5

What is the electronic structure of Aluminium?

Answer 5

2, 8, 3

Question 6

How can you tell the number of electrons in the outermost (highest) energy level by looking at the group of the element?

Answer 6

The number of electrons in the outermost shell is the same number as the group its in.
For example, Oxygen is in group 6 and has an electronic figure of 2, 6

Question 7

What determines the reactivity of an atom?

Answer 7

The number of electrons it has in its outermost shell

Question 8

Why do elements in the same group react similarly?

Answer 8

Elements of the same group have the same number of electrons in the outermost shell, therefore they will react similarly

Question 9

Which group is known as the noble gases?

Answer 9

Group 0 elements are known as noble gases because they are unreactive