Question

based on the information in the table, which two elements are most likely in the same group, and why? facts about four elements element atomic mass (amu) total electrons valence electrons year isolated bismuth (bi) 209 83 5 1753 nitrogen (n) 14 7 5 1772 oxygen (o) 16 8 6 1772 sodium (na) 23 11 1 1807 thallium (tl) 204 81 3 1861 bismuth and thallium, because their atomic masses are very similar nitrogen and oxygen, because they were both first isolated in the same year sodium and thallium, because their names both end in the same suffix: -um bismuth and nitrogen, because they have the same number of valence electrons

Explanation:

To determine elements in the same group, we use the periodic table rule: elements in the same group have the same number of valence electrons (they share similar chemical properties). Let's analyze each option:

1. Bismuth (Bi) and Thallium (Tl): Atomic mass similarity does not determine group placement. Grouping is based on valence electrons/chemical properties, not atomic mass. Eliminate this.
2. Nitrogen (N) and Oxygen (O): Isolation year is irrelevant to periodic table grouping. Grouping depends on electron configuration/valence electrons. Eliminate this.
3. Sodium (Na) and Thallium (Tl): Suffix "-um" is a naming convention (e.g., Latin roots) and does not relate to chemical properties or group placement. Eliminate this.
4. Bismuth (Bi) and Nitrogen (N): Both have 5 valence electrons. In the periodic table, elements with the same valence electron count belong to the same group (e.g., Group 15 for N and Bi, as they have 5 valence electrons). This matches the rule for group classification.

Answer:

bismuth and nitrogen, because they have the same number of valence electrons