Question

choose the correct noble gas/abbreviated/shorthand/condensed notation for the electron configuration of br. which one of the following is the correct shorthand notation of the electron configuration of br? view available hint(s) 1s²2s²2p⁶3s²3p⁶4s²3d¹⁰4p⁵ ar 4s²4p⁵ ne 3s²3p⁵ ar 4s²3d¹⁰4p⁵ submit first choice (top) second choice third choice fourth choice (bottom)

Explanation:

Step1: Determine Br's atomic number

Bromine (Br) has an atomic number of 35, so it has 35 electrons.

Step2: Identify the noble gas before Br

The noble gas with electron configuration closest to Br (but with fewer electrons) is Argon (Ar), which has 18 electrons.

Step3: Write the electron configuration after [Ar]

After [Ar] (18 electrons), we need to account for 35 - 18 = 17 more electrons. The electron configuration for these electrons follows the order: 4s², 3d¹⁰, 4p⁵ (because 4s fills before 3d, and then 4p). So the condensed notation should be [Ar] 4s² 3d¹⁰ 4p⁵.

Step4: Evaluate the options

• First choice: Full electron configuration, not condensed (uses noble gas abbreviation), so incorrect.
• Second choice: Missing 3d¹⁰ (after 4s², 3d fills before 4p in transition metals, and Br is a halogen with 3d filled), so incorrect.
• Third choice: [Ne] is for 10 electrons, then 3s²3p⁵ would be Cl, not Br, so incorrect.
• Fourth choice: [Ar] 4s² 3d¹⁰ 4p⁵ matches the calculation, so correct.

Answer:

fourth choice (bottom)