Chemistry Reference
In-Depth Information
6.
[F.]—Aluminum, with the electron configuration of 1s
2
2s
2
2p
6
3s
2
3p
1
, has 3
valence electrons.
7.
[C.]—Nitrogen, with the electron configuration of 1s
2
2s
2
2p
3
, has 5 valence
electrons.
8.
[E.]—Fluorine, with the electron configuration of 1s
2
2s
2
2p
5
, has 7 valence
electrons.
Lesson 3 - 7 Review
1.
[atomic]—Remember: It is the atomic number that determines the atoms'
identity.
2.
[metalloids or semiconductors]—Semimetal tends to be better conductors
than nonmetals but worse conductors than metals, hence the term
semiconductors.
3.
[groups]—Just as members of your family may share certain physical
characteristics, elements in a family have similar properties.
4.
[periods]—The periodic table has seven periods and room to grow.
5.
[alkali metals]—Alkali metals are extremely reactive. They took a long time
to be discovered because they are only found in nature as part of other
compounds.
6.
[metals]—You may have noticed that almost all of the metals are solids at
room temperature.
Chapter 3 Examination
1.
[c. electron]
2.
[f. kernel]—Think of a kernel of popcorn. Valence electrons are not
included in the kernel.
3.
[d. mass number]—Because the electrons have essentially no mass, the
protons and the neutrons make up the vast majority of the mass of an atom.
4.
[l. orbital]—Orbitals are not always full, but when they are, they can hold a
maximum of two electrons.
5.
[i. positive]—Remember, losing negative charges (electrons) leaves an atom
with “extra” positive charges.
6.
[j. quantum numbers]
7.
[e. atomic number]—The atomic number is also equal to the nuclear charge
of an atom.
8.
[g. negative]—When a neutral atom gains extra negative charges, it will
have a net negative charge.
9.
[a. proton]
