During electron capture, a proton in the nucleus is converted into a neutron. Here's how it works:

* Electron capture: An electron from an inner electron shell of the atom is captured by a proton in the nucleus.

* Conversion: The captured electron combines with the proton, resulting in the emission of an electron neutrino and the transformation of the proton into a neutron.

* Atomic change: This process decreases the atomic number of the atom by one while leaving the mass number unchanged. The atom becomes a different element.

Here's the equation:

```

p + e⁻ → n + νₑ

```

Where:

* p = proton

* e⁻ = electron

* n = neutron

* νₑ = electron neutrino