What change occurs in the atomic structure during beta decay, and how does it affect the periodic table?

A proton is converted into a neutron, decreasing the atomic number by 1, moving the element to the previous position in the periodic table.

An electron is added to the nucleus, increasing the atomic mass by 1, but not affecting the atomic number.

A neutron is converted into a proton, increasing the atomic number by 1, moving the element to the next position in the periodic table.

A neutron is converted into an electron, decreasing the atomic mass by 1, but not affecting the atomic number.