Question

there are 3 shells in the atom of an element its outer most shel contai s 3 electrons and mass number of the element is 27. a how many electrons and neutrons are there?.​

Answer 1

Answer:

There are three shells in the atom of an element it's outer most shell contains 3 electrons.

Explanation:

Number of shells is same as number of period.

i.e. The element is in third period.

Let the element be X.

=> Electronic configuration will be (2, 8, 3)

>> Atomic number (Z) of X is 13.

>> The element is Aluminum.

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Calculation:

Here,

Z = 13 and A = 27

Atomic number is same as number of protons in an element.

Therefore, number of protons is 13.

Atomic mass = Number of protons + Number of neutrons

=> 27 = 13 + Number of neutrons.

=> Number of neutrons = 14.

An atom as same number of electrons and protons.

i.e. Number of electrons = 13.

Therefore, their are 13 electrons and 14 neutrons.