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Question
Elements A, B and C have atomic numbers 9, 20 and 10 respectively.
- State which one is
(1) a non-metal,
(2) a metal,
(3) chemically inert.[A,B,C] - Write down the formula of the compound formed by two of the above elements.[BA2]
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Solution
- 9A 20B 10C
Atomic number of:
A = 9 = number of electrons = 2, 7
B = 20 = number of electons = 2, 8, 8, 2
C = 10 = number of electrons = 2, 8
(1) A non-metal = A
(2) A metal = B
(3) Chemically inert = C - Compound formed is A1−, B2+
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