2006-10-30 13:19:50 · 4 answers · asked by kintz2010 1 in Science & Mathematics ➔ Physics
A valence electron is an electron which lies in the outer energy level of an atom. Helium has 2. Aluminum has 3.
2006-10-30 13:24:06 · answer #1 · answered by Anonymous · 1⤊ 0⤋
Atoms have "energy levels" or "rings" of electrons, and the electrons in the outer level are the valence electrons. Aluminum is in family 13 on the periodic table, so it has 3 valence electrons. Helium has 2 valence electrons, only 1 ring, and the first ring is full with 2, so it won't combine with other atoms and make compounds. The ones that make compounds the most readily are the ones in families 1, 2, (they have 1 and 2 valence electrons), and families 16 and 17 (they have 6 and 7 respectively). All atoms want to have 8, so they combine with other atoms. EX: Na (1) and Cl (7) are the perfect couple...NaCl, table salt.
2006-10-30 21:27:59 · answer #2 · answered by macjetsfan 3 · 0⤊ 0⤋
Hi. Helium has room for two electrons in it's shell and it HAS two. That's why it is inert. It doesn't need or share electrons. Take a fresh look at aluminum.
2006-10-30 21:23:40 · answer #3 · answered by Cirric 7 · 0⤊ 1⤋
two electrons
2006-10-30 21:31:59 · answer #4 · answered by J 6 · 0⤊ 0⤋