Question

Hey friend!! How to calculate atomic mass and valency ??
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Answer 1

Explanation:

Atomic mass is sum of protons and neutrons.

And valency for first four groups is their group number itself but from fifth group you have to subtract from 8 like: fifth group:8-5=3.

sixth group:8-6=2 .and so on

Answer 2

Answer:

To calculate the atomic mass of a single atom of an element, add up the mass of protons and neutrons. Example: Find the atomic mass of an isotope of carbon that has 7 neutrons. You can see from the periodic table that carbon has an atomic number of 6, which is its number of protons.

The valency of an atom is equal to the number of electrons in the outer shell if that number is four or less. Otherwise, the valency is equal to eight minus the number of electrons in the outer shell. Once you know the number of electrons, you can easily calculate the valency.