Based on the information in the table, which elements are most likely in the same periods of the periodic table?
| Element | Atomic mass (amu) | Total electrons | Valence electrons | Year isolated |
| -------------- | ----------------- | --------------- | ----------------- | ------------- |
| Aluminum (AI) | 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 |
A. 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.
B. 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.
C. 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."
D. Aluminum, boron, and gallium are likely together in one group because they have the same number of valence
Answer (2)
Elements in the same period have the same number of electron shells.
Determine the number of electron shells for each element based on the number of total electrons.
Boron and Carbon are in period 2.
Gallium and Germanium are in period 4.
Aluminum is in period 3.
Therefore, Boron and Carbon are in the same period, and Gallium and Germanium are in the same period. B oro nan d c a r b o n , g a ll i u man d g er mani u m
Explanation
Understanding the Problem We are given a table with information about five elements: Aluminum (Al), Boron (B), Carbon (C), Gallium (Ga), and Germanium (Ge). The information includes atomic mass, total electrons, valence electrons, and year isolated for each element. The question asks which elements are most likely in the same periods of the periodic table based on the given information.
Determining Electron Shells Elements in the same period have the same number of electron shells. The number of electron shells corresponds to the period number. We can determine the number of electron shells for each element based on the number of total electrons.
Aluminum's Period Aluminum (Al) has 13 electrons. Its electron configuration is 2-8-3, meaning it has 3 electron shells. Therefore, Aluminum is in period 3.
Boron's Period Boron (B) has 5 electrons. Its electron configuration is 2-3, meaning it has 2 electron shells. Therefore, Boron is in period 2.
Carbon's Period Carbon (C) has 6 electrons. Its electron configuration is 2-4, meaning it has 2 electron shells. Therefore, Carbon is in period 2.
Gallium's Period Gallium (Ga) has 31 electrons. Its electron configuration is 2-8-18-3, meaning it has 4 electron shells. Therefore, Gallium is in period 4.
Germanium's Period Germanium (Ge) has 32 electrons. Its electron configuration is 2-8-18-4, meaning it has 4 electron shells. Therefore, Germanium is in period 4.
Conclusion Based on the number of electron shells, Boron and Carbon are in the same period (period 2), and Gallium and Germanium are in the same period (period 4). Aluminum is in period 3.
Examples
Understanding the periodic table and the arrangement of elements into periods and groups is fundamental in chemistry. For example, when designing new materials with specific properties, chemists consider the electron configurations of elements to predict their bonding behavior and reactivity. Elements in the same period exhibit trends in properties such as electronegativity and ionization energy, which are crucial in chemical reactions and material synthesis.
Boron and Carbon are in Period 2 because they have 2 electron shells, while Gallium and Germanium are in Period 4 as they have 4 electron shells. Thus, the correct option is A.
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