Element X has the electronic configuration 2.8.7
(a) State the group and the period of element X in the Periodic Table. [2]
(b) State whether element X is a metal or a non-metal. Give a reason based on its electronic configuration. [1]
(c) Explain why the elements in Group 0 are unreactive. [2]
- (a) group 7 (accept group VII or group 17)(1)
- (a) period 3(1)
- (b) non-metal and it has 7 outer (shell) electrons / it gains (one) electron to form an ion / it is one electron short of a full outer shell(1)
- (c) (atoms have) a full outer shell (of electrons) / stable arrangement (accept 8 outer electrons; helium 2)(1)
- (c) so they do not (need to) lose, gain or share electrons(1)
- Answer: (a) group 7, period 3 (b) non-metal (c) full outer shell so no tendency to lose/gain/share electrons
- Examiner tip: Period = number of occupied shells; group = number of outer-shell electrons. Students regularly swap them.