2007-01-14 04:26:39 · 4 answers · asked by Anonymous in Science & Mathematics ➔ Chemistry
electron shells!!! Periods are horizonal...groups or families are vertical
2007-01-14 04:35:26 · answer #1 · answered by The Cheminator 5 · 0⤊ 0⤋
elements belonging to the same period are located in the same energy level varying only in the number of valence electrons. the variation of valence electrons is a major factor that influence the trends in the properties of elements along a row of the periodic table
2007-01-14 04:38:03 · answer #2 · answered by mn3mosyne 2 · 0⤊ 0⤋
They have the same number of electrons in their outer orbitals. For instance, the first period (alkaline metals) has one electron in it's outer orbital, and so they all lose this electron when they react with other atoms, and thus they all react in the same way.
2007-01-14 04:32:08 · answer #3 · answered by Suzanne 2 · 0⤊ 1⤋
Valence electrons.
2007-01-14 05:10:18 · answer #4 · answered by Brendan R 4 · 0⤊ 0⤋