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<p>I wonder why the third shell can hold 8 electrons. I thought M is the 3s 3p 3d, which can hold up to 18: 3s–2 3p–6 3d–10</p>
<p>2+6+10=18 ???</p>
<p>What do you think?</p>
<p>Isn’t the order of electron level…shells “3s2, 3p6, 4s2, 3d10”?
If you look at the periodic table, 4s2, 3d10 (the transition metals) are in the next period down.</p>
<p>But I only mention the third shell.
This shell can hold 18 electrons at most. But the book says it can hold 8???</p>
<p>Yeah…the third shell is 3s2 3p6 –> 2 + 6 = 8
Period 1 has a max of 2 valence electrons –> 1s2
Period 2 has a max of 8 –> 2s2, 2p6
Period 3 has a max of 8 –> 3s2 3p6
Period 4 has a max of 16 –> 4s2 3d10 4p6
etc.</p>
<p>The book is wrong, at the very least in its terminology. CDN_Dancer, you’re looking at the order in which shells are filled in a neutral atom, but you’re splitting up actual shells; “4s2, 3d10, 4p6” is NOT a shell. A shell is 4s2, 4p6, 4d10, 4f14, for example.</p>
<p>So shell 1, or n=1, can hold 2 (1s2).
Shell 2, or n=2, can hold 8 (2s2, 2p6).
Shell 3, or n=3, can hold 18 (3s2, 3p6, 3d10), even though the subshells are not filled in this order in a neutral atom.
Shell 4, or n=4, can hold 32 (4s2, 4p6, 4d10, 4f14)
…and so on.</p>
<p>Thanks, everyone.
I agree with GoldShadow!</p>