An element T has the electronic configuration 2,8,7
(a)What is the group number of T?
(b)What is the period number of T?
(c)How many valence electrons are there in an atom of T?
(d)What is the valency of T?
(e)Is it a metal or a non-metal?
(f)State the number od protons and neutrons.
Answers
Since no. electrons in outermost shell are 7 hence it belongs from 17th group.
Since total electrons are filled in 3 shells like 2,8,7 and no. Of shells are equal to no. Of period hence no. Of period are 3.
Since Valence electrons are the total no. Of electron present in Valence shell i . e. Outermost shell which are 7.
Since Valency is the no. Of electron required to complete it's octet I.e. 8 electron in Valence shell hence valency= 8-7= 1
Metals are those which contain 1,2,3 electrons in Valence shell or have tendency to lose electron to complete octet where as non metals are those which contain 5,6,7 electrons in Valence shell or have tendency to gain electron to complete it's octet hence The is non metal.
Total No. Of protons in an atom = total no. Of electron= atomic no. Of an atom which is 17 for T
No. Of neutrons = mass no.- no. Of protons
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