Question

define shells, valency and lsobar
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Answer 1

Answer:

1. a hard covering that protects eggs, nuts and some animals.

2. a measurement of the power of an atom to combine with others, by the number of hydrogen atoms it can combine with or take the place of.

3.a line on a weather map that joins places that have the same air pressure at a particular time.

Answer 2

Shells -the hard protective outer case of a mollusc or crustacean.

Valency-Valency is the combining power of an element. Elements in the same group of the periodic table have the same valency. The valency of an element is related to how many electrons are in the outer shell. Group number.

Isobar -Isobars are atoms (nuclides) of different chemical elements. ... Isobars: Atoms of different elements with different atomic numbers, which have the same mass number, are known as isobars. Isotopes have the same number of protons so their atomic numbers and chemical properties are the same.