Question

give the electron configuration for indium. you must use the noble gas configuration (the shortcut) valence electrons

Explanation:

Step1: Identify noble - gas core

Indium (In) has an atomic number of 49. The nearest noble gas with a lower atomic number is krypton (Kr) which has an atomic number of 36. So, we start with [Kr].

Step2: Determine remaining electrons

49 - 36=13 remaining electrons to account for.

Step3: Fill orbitals after noble - gas core

The next orbitals are 4d, 5s, and 5p. The 4d sub - shell can hold 10 electrons, the 5s sub - shell can hold 2 electrons, and the 5p sub - shell starts to be filled. After filling 4d¹⁰ and 5s², we have used 10 + 2 = 12 electrons out of the 13 remaining. The last electron goes into the 5p sub - shell. So the electron configuration is [Kr]4d¹⁰5s²5p¹.

Step4: Find valence electrons

Valence electrons are the electrons in the outermost shell. For indium with the configuration [Kr]4d¹⁰5s²5p¹, the outermost shell is the 5th shell. The number of electrons in the 5th shell is 2 (in 5s) + 1 (in 5p)=3.

Answer:

[Kr]4d¹⁰5s²5p¹; 3