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Question
An element A atomic number 7 mass numbers 14
B electronic configuration 2,8,8
C electrons 13, neutrons 14
D Protons 18 neutrons 22
E Electronic configuration 2,8,8,1
State Valency of each element
An element A atomic number 7 mass numbers 14
B electronic configuration 2,8,8
C electrons 13, neutrons 14
D Protons 18 neutrons 22
E Electronic configuration 2,8,8,1
State (i) Valency of each element (ii) which one is a metal (iii) which is non-metal (iv) which is an inert gas
Solution
(i) Element A
Atomic number = 7 = Number of electrons = 2, 5
Valency of A = 8 - 5 = 3
Element B
Electronic configuration 2, 8, 8
Valency of B = Zero
Element C has 13 electrons
Electronic configuration = 2, 8, 3
Valency of C = 3
Element D
Protons = 18 = Electrons = 2, 8, 8
Valency of D = Zero
Element E
Electronic configuration = 2, 8, 8, 1
Valency of E = 1
(ii) C and E are metals.
(iii) A is a non-metal.
(iv) A, C and E are not inert gases.
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