Calcium chloride
2 marks · NormalDraw a dot-and-cross diagram to represent the ionic bonding in lithium fluoride.
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Must show: Li atom with 2,8 electron arrangement after losing one electron, F atom with 2,8 electron arrangement after gaining one electron, electrons shown as dots and crosses (distinguishing between atoms), correct charges on ions: Li^+ and F^-, clear transfer of 1 electron from Li to F
Also accept: Electrons shown as symbols distinctive between atoms (all dots/crosses or other, so long as electrons are distinguished)
Common mistakes: Incorrect number of electrons in shells; No charge shown on ions; Electrons not transferred
Show mark scheme and worked solution
Marking points
M1 · 1 mark · Diagram shows Li and F with correct arrangements (Li 2,8; F 2,8), with distinctive dot/cross electrons
A1 · 1 mark · One electron is shown as transferred, ions are shown with correct charges (Li^+, F^-)
Worked solution
Li (lithium) originally has one electron in its outer shell; fluorine (F) needs one more electron for a full outer shell.