Question

An atom has 5 electrons in M shell than (a) Find out its atomic number? (b) Write Electronic configuration of atom? (c) Name element of atom?

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Answer 1

Answer:

15

1s2 2s2 2p6 3s2 3p3

phosporus(P)

Explanation:

The shell of principal quantum number n=1 is K shell, n=2 is L shell and n=3 is M shell. M shell has three subshells- s,p,d. And n=3 is not a fully filled shell as it has 5 electrons. So it is the outermost shell.

3s subshell has a maximum of 2 electrons, so the rest of the three electrons will be in 3p

The electronic configuration is 1s2 2s2 2p6 3s2 3p3

The atomic number is 2+2+6+2+3=15

The element of the atom is phosporus(P)

Answer 2

ELECTRONIC CONFIGURATION -

• The representation of the location of the electrons in an atom.
• The electrons revolve around the nucleus in fixed orbitals or shells.
• The shells are K, L, M, and N based on the increasing level of energy.
• The K shell can fill 2 electrons, L - 8 electrons, M can have 18 electrons and N has the capacity for 32 electrons.
• The sum of electrons will give the atomic number of the respective element.

(i) In the given problem, the atom with 5 electrons in the M shell, will have fully-filled K and L shells.

The total number of electrons in the atom = 2 + 8 + 5 = 15

Atomic number = Total number of electron in the atom.

Atomic number = 15

(ii) The electronic configuration of the element with atomic number 15 can be given as -

$1s^22s^22p^63s^23p^3$

The K shell has only one subshell s, L has two orbitals s, and p, and L orbit has three subshells classified as s, p, and d.

The s subshell can accommodate only 2 electrons, p can have 6 electrons as its maximum ability and d subshell can fill 10 electrons.

(iii) The element containing 15 electrons in its atom with 5 electrons in its M shell will be present in the 15th group of the periodic table.

The element in its native present with 5 valence electrons is PHOSPHORUS.