Question

facts about five elements
element atomic mass (amu) total electrons valence electrons year isolated
aluminum (al) 27 13 3 1825
boron (b) 11 5 3 1808
carbon (c) 12 6 4 1803
gallium (ga) 70 31 3 1875
germanium (ge) 73 32 4 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 \ium.\
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.

Explanation:

Step1: Recall periodic - table concepts

Elements in the same group have the same number of valence electrons, and elements in the same period have the same number of electron shells and are arranged in order of increasing atomic number. Atomic mass and the year of isolation are not the criteria for determining periods or groups. The ending of element names is also not a valid criterion.

Step2: Analyze the options

Aluminum (Al), boron (B), and gallium (Ga) all have 3 valence electrons, so they are likely to be in the same group. Carbon (C) and germanium (Ge) both have 4 valence electrons, so they are likely to be in the same group.

Answer:

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.