Chemistry Reference
In-Depth Information
Using the arrow diagram to determine the order for filling the sublevels,
and placing 2 electrons in each s sublevel and 6 in each p sublevel, we run
out of electrons when the 4s sublevel has 1 electron in it. We can check our
answer by making sure that the sum of all the superscripts is equal to 19.
6.
[1s
2
2s
2
2p
6
3s
2
3p
6
4s
2
3d
10
4p
6
]—Krypton has 36 electrons and a complete
octet. Notice that there are a total of 8 electrons in the fourth (valence)
energy level of this atom, giving it the special stability of a noble gas.
Lesson 3 - 5 Review
1.
[orbitals]—Remember that in some topics the orbitals are represented with
squares.
2.
[electrons]—Slash marks are also used to represent electrons, in some
topics.
3.
[C.]—The orbital notation shown in answer C shows 17 arrows,
representing the 17 electrons in the chlorine atom.
4.
[D.]—Helium, with an electron configuration of “1s
2
,” can be represented
by the orbital notation shown in answer D.
5.
[A.]—A neutral atom of fluorine has 9 electrons, as does the orbital
notation shown in answer A.
6.
[F.]—Lithium, with an electron configuration of “1s
2
2s
1
,” can be
represented by the orbital notation shown in answer F.
7.
[E.]—The orbital notation shown in answer E shows 12 arrows,
representing the 12 electrons in a neutral atom of magnesium.
8.
[B.]—Boron, with an electron configuration of “1s
2
2s
2
,” can be represented
by the orbital notation shown in answer B.
Lesson 3 - 6 Review
1.
[electrons]—More specifically, the dots represent the valence electrons.
2.
[the electrons in the valence shell]—Only the outer energy level electrons
as shown as dots in a Lewis dot diagram. Inner electrons, which are part of
the “kernel” of the atom, are represented along with the nucleus by the
elemental symbol.
3.
[B.]—Helium, with the electron configuration of 1s
2
, has 2 valence electrons.
4.
[D.]—Lithium, with the electron configuration of 1s
2
2s
1
, has only 1 valence
electron.
5.
[A.]—Oxygen, with the electron configuration of 1s
2
2s
2
2p
4
, has 6 valence
electrons.
