Element
Aluminum (Al)
Boron (B)
Carbon (C)
Gallium (Ga)
Germanium (Ge)
Facts about Five Elements
Total
electrons
13
5
Atomic
mass (amu)
27
11
12
70
73
6
31
32
Valence
electrons
3
3
4
3
4
Year isolated
1825
1808
1803
1875
1886
Boron and carbon are likely together in one period because they have very close atomic masses, while gallium and
germanium are likely together in another period because they have very close atomic masses.
Aluminum, boron, and carbon are likely together in one period because they were first isolated in the first half of the
1800s, while gallium and germanium are likely together in another period because they were first isolated in the
second half.
Boron and carbon are likely together in one period because they each end in "-on," while aluminum, gallium, and
germanium are likely together in another period because they each end in "-lum."
O Aluminum, boron, and gallium are likely together in one group because they have the same number of valence
electrons, and carbon and germanium are likely together in another group because they have the same number of
valence electrons.