5. (a) What are isobars?
(6) Atomic number of an element Y is 17.
(1) Write its electronic configuration.
(ii) What is the number of valence electrons
in Y ?
(iii) How many electrons are needed to complete
the octet of Y ?
(iv) Is it a metal or non-metal ?
(c) The valency of Na is 1 and not 7. Give reason.
Answers
5.(a) Isobars are the elements which have different atomic numbers but same atomic mass.
(b)
(i) Y - 2,8,7
(ii) There are 7 valence electrons in Y
(iii) Only 1 electron is need.
(iv) It is a non metal.
(c) The valency of Na is 1 because it has only one valence electron and it is easier to lose one electron to achieve its octet configuration than gaining seven electrons.
Answer:
5. Isobars are atoms of different chemical elements that have the same number of nucleons(Protons+Neutrons). Isobars differ in atomic number but have the same mass number.
6. (a) Electronic configuration of an element Y of atomic number 17 is
1s2 2s2 2p6 3s2 3p5
(b) Number of valence electrons in Y are 2+5=7
(c) Number of electrons needed to complete the octet of Y are 1.
(d) Y is a Non-metal.
(e) The valency of Na is 1 and not 7 because it is the 1st group element.
Explanation:
Hope this helps you..