Look at the periodic table. When Be loses it\'s first electron it now only has 3 electroms (Just like Li) when it loses it\'s second electron in only has 2 electrons (just like He) when it loses it\'s third electron it goes from 1s2 to 1s1 therefore the 1s orbital loses an electron in the third ionization step for Be Solution Look at the periodic table. When Be loses it\'s first electron it now only has 3 electroms (Just like Li) when it loses it\'s second electron in only has 2 electrons (just like He) when it loses it\'s third electron it goes from 1s2 to 1s1 therefore the 1s orbital loses an electron in the third ionization step for Be.