Question

use the periodic table to answer the question. which element has atoms with valence electrons in a higher energy level than those of calcium (ca)? (1 point) ○ oxygen (o) ○ lithium (li) ○ cesium (cs) ○ bromine (br)

Explanation:

Step1: Determine Ca's energy level

Calcium (Ca) is in period 4, so valence electrons are in energy level \( n = 4 \).

Step2: Analyze each option

• Oxygen (O): Period 2, \( n = 2 \) (lower than 4).
• Lithium (Li): Period 2, \( n = 2 \) (lower than 4).
• Cesium (Cs): Period 6, \( n = 6 \) (higher than 4). Wait, but option is "cerium (Ce)"? Wait, typo? Wait, original options: "cesium (Cs)"? Wait, no, the option is "cerium (Ce)"? Wait, no, looking at the periodic table, Ce is in period 6 (lanthanides, period 6). Wait, but let's check bromine (Br): Br is in period 4, \( n = 4 \) (same as Ca). Wait, maybe a typo, but cesium (Cs) is period 6. Wait, the option is "cerium (Ce)"? Wait, no, the user's options: "oxygen (O)", "lithium (Li)", "cerium (Ce)", "bromine (Br)". Wait, Ce is in period 6 (lanthanide, period 6). So Ce's valence electrons are in \( n = 6 \), which is higher than Ca's \( n = 4 \). Wait, but let's re - check:

Ca is in group 2, period 4. Its electron configuration is \([Ar]4s^{2}\), so valence energy level \( n = 4 \).

• O: period 2, \( n = 2 \).
• Li: period 2, \( n = 2 \).
• Ce: period 6 (lanthanides are in period 6), electron configuration involves \( 6s \) (valence level \( n = 6 \)).
• Br: period 4, \( n = 4 \) (same as Ca).

So Ce (cerium) has valence electrons in a higher energy level (\( n = 6 \)) than Ca (\( n = 4 \)).

Answer:

cerium (Ce)