Question

protons and isotopes quick check
which statement describes the number of protons in each atom of an element? (1 point)
the number of protons is given by the mass number, which increases by one moving from left to right across each row of the periodic table
the number of protons is given by the atomic number, which increases by one moving from left to right across each row of the periodic table.
the number of protons is given by the atomic number, which increases by one moving down in its column in the periodic table
the number of protons is given by the mass number, which increases by one moving down in its column in the periodic table

Explanation:

The atomic number of an element is defined as the number of protons in the nucleus of an atom of that element. As we move from left - to - right across a period (row) in the periodic table, the atomic number increases by one. The mass number is the sum of protons and neutrons and is not the same as the number of protons.

Answer:

The number of protons is given by the atomic number, which increases by one moving from left to right across each row of the periodic table.