Answer:
B. Cl.
Explanation:
These are Group 7 elements whose reactivity reduces as you go down the group. Chlorine has a smaller atoms than the rest and has a stronger tendency to grab an electron in its valency shell. This is because its nucleus is closer to the outer electrons than the other elements.
Answer:
Average atomic mass = 79.9035 amu.
The given element is bromine.
Explanation:
Given data:
Mass of 1st isotope = 78.9183 amu
Percent abundance of 1st isotope = 50.69%
Mass of 2nd isotope = 80.9163 amu
Percent abundance of 1st isotope = 49.31%
Average atomic mass = ?
Solution:
Average atomic mass = (abundance of 1st isotope × its atomic mass) +(abundance of 2nd isotope × its atomic mass) / 100
Average atomic mass = (50.69×78.9183 )+(49.31× 80.9163) /100
Average atomic mass = 4000.3686+ 3989.9828 / 100
Average atomic mass = 7990.3514 / 100
Average atomic mass = 79.9035 amu.
The given element is bromine.
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