Drawing diagrams of electronic configurations
4 marks · NormalThe table below shows the electronic configurations of four elements, labelled A, B, C and D.
| Element | Number of electrons in each shell |
|---|---|
| A | 2, 8, 1 |
| B | 2, 6 |
| C | 2, 8 |
| D | 2, 5 |
Which element has the largest number of shells?
Which element has a full outer shell?
Which element is likely to be chemically unreactive? Give a reason for your answer.
How many electrons are in the outer shell of element D?
Work this out on paper, then compare with the answer and worked solution below. With a free account you can submit written answers for marking.
Show answer
(a) A · must show Element with three shells
(b) C · must show Element with full second shell (8 electrons)
(c) C is chemically unreactive because it has a full outer shell of electrons. · must show Identifies C, Explains full outer shell = unreactive
(d) 5 · must show Last number in D's configuration = 5
Show mark scheme and worked solution
Marking points
B1 (a) · 1 mark · Correctly identifies element with most shells (A: 2,8,1 = three shells).
B2 (b) · 1 mark · Correctly identifies element with full outer shell (C: 2,8).
E1 (c) · 1 mark · Identifies C as unreactive because it has a full outer shell.
A1 (d) · 1 mark · States number of electrons in outer shell of D: 5.
Worked solution
a) A has three shells (2, 8, 1).
b) C has a full outer shell (2, 8).
c) C is unreactive as its outer shell is full.
d) D has 5 electrons in its outer shell (2, 5).