How many atoms are there in 90.2 g of selenium?
1 answer:
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Answer:
The nuclear charge increases, but the number of inner shielding electrons stays the same.
Explanation:
Their shielding does not change, so the effective nuclear charge — the charge felt by a valence electron — increases.
The valence electrons are pulled closer to the nucleus, decreasing the atomic radius.
For example, consider the elements of Period 3.
The number of protons increases as you go from one element to the next, but the number of inner electrons is constant.
