Calcium chloride
3 marks · Easy| Element | Number of outer shell electrons |
|---|---|
| Lithium (Li) | 1 |
| Sodium (Na) | 1 |
| Fluorine (F) | 7 |
| Chlorine (Cl) | 7 |
State the electronic configuration of a lithium atom.
Colour or underline the value in the table that shows how many electrons a fluorine atom has in its outer shell.
Using information from the table, explain why lithium and fluorine are likely to react together to form an ionic compound.
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) 2,1
(b) 7 · must show Identifies 7 as number of outer electrons for F from table
(c) — · must show Cites transfer of 1 electron from Li to F, forming ions
Show mark scheme and worked solution
Marking points
B1 (a) · 1 mark · Correctly gives lithium atom's electronic configuration as 2,1.
B1 (b) · 1 mark · Identifies 7 as the outer shell electron number for F.
M1 (c) · 1 mark · Explains that lithium can lose 1 electron and fluorine can gain 1 electron to form ions, forming an ionic compound.
Worked solution
a) The electronic configuration of lithium is 2,1. b) The value for fluorine's outer shell electrons is 7. c) Lithium has 1 electron in its outer shell it can lose, and fluorine has 7 and needs 1 more to have a full shell. Therefore, lithium transfers its 1 electron to fluorine, forming Li^+ and F^- ions and making an ionic compound.