Question

If an atom A has atomic number 19 and mass number 39, state its

(i) Number of protons

(ii) Number of electrons

(iii) Number of neutrons

(iv) Electronic configuration

(v) Number of valence electron

(vi) Valency ​

Answer 1

Answer:

Electronic configuration

Answer 2

Explanation:

at.no .represented as Z and mass number represented as A

Z=no. of protons = no. of electrons

A=no.of protons + no.of neutrons

so,

1.no. of protons = Z=19

2.no. of electrons=Z=19

3.A=no.of prtons + no.9f neutron

39 =19+neutrons

neutrons=39 -19 =20

4.electronic configuration is the distributions of electrons in the shells or orbits . so,

elec.config=2,8,9

5. no. of valence electrons=9

6. it will give away one electron to have a stable electronic configuration and will thus become a. cation and carry a positive charge ...so valency of atom A is 1+

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