Question

Question #d4d86

Answer 1

THe answer is d) `""_15^(32)"P"` and `""_16^(32)"S"`.

Explanation:

In order for two atoms that belong to different elements to be isobars, the must have the same mass number, `A`.

The mass number of an atom is equal to the sum of its protons and neutrons.

`A = Z + N`, where

`Z` - the number of protons the atom has, equal to the atomic number;
`N` - the number of neutrons it has;

For any element, the mass number is located in the upper left of the chemical symbol, while the atomic number is located in the bottom left of the symbol.

http://hyperphysics.phy-astr.gsu.edu/hbase/nuclear/nucnot.html

So, all you have to do to determine which of those pairs is isobaric is to take a look at the number located in the upper left of the symbol.

For `""_6^(12)"C"` and `""_7^(14)"N"`, you have different mass numbers, `12` and `14`, respectively, so these two atoms are not isobaric.

The same can be said for `""_4^9"Be"` and `""_5^(11)"B"` (`9cancel("=")11`) and for `""_1^1"H"` and `""_1^2"D"` (`1cancel("=")2`).

However, if you take a look at the atoms in the last pair, you'll notice that their mass numbers are indeed equal, which makes them isobaric.

`""_15^(32)"P"` and `""_16^(32)"S"-> 32=32 => color(green)("isobaric")`