1.) which of the following have the correct sequence of orbitals in a multi electron atom from lowest to highest energy? if the orbitals are not in order of increasing energy, put them in the correct order.
2p < 3s < 2s
3p < 4s < 3d
3p < 3d < 4s
2p < 2s < 1s
3s < 4s < 3p
2.) rewrite the electron configurations for the atoms below using core electron notation.
determine the number of valence electrons for each atom.
b 1s22s22p1
ca 1s22s22p63s23p64s2
cl 1s22s22p63s23p5
3.)the following electron configurations correspond to neutral atoms in excited states. what is the element and what is the ground state electron configuration for each atom?
1. 1s2 2s2 2p6 3s2 3p6 3d5
2. [kr] 5s2 4d10 5p4 6s1

Explanation:

The sublevels are shown below and have been arranged from their lowest to highest energy levels:

  1s 2s 2p 3s 3p 4s 3d 4p 5s 4d 5p 6s 4f 5d 6p 7s 5f e.t.c

1. 3p < 4s < 3d is properly arranged.

Re-arranging properly:

2p < 3s < 2s = 2s < 2p < 3s

3p < 3d < 4s = 3p < 4s < 3d

2p < 2s < 1s  = 1s  < 2s < 2p

3s < 4s < 3p = 3s < 3p < 4s

2. The core electron notation simply means writing the electronic configuration with the inner electrons mimicking the nearest noble gases:

 B  1s²2s²2p1¹ = [He] 2s²2p1¹

Ca   1s² 2s² 2p⁶ 3s² 3p⁶ 4s²  = [Ar] 4s²

Cl  1s² 2s² 2p⁶ 3s² 3p⁵ = [Ne] 3s² 3p⁵

For boron, the valence electron is 3

For Ca, the valence electrons is 2

For Cl, the valence electrons is 7

3.  

1. 1s² 2s² 2p⁶ 3s² 3p⁶ 3d⁵

The element has 23 electrons and this Manganese:

Ground state configuration should be

 1s² 2s² 2p⁶ 3s² 3p⁶ 4s² 3d³

2.  [Kr] 5s² 4d¹⁰ 5p⁴ 6s¹

The element has 53 electrons and it is iodine

The ground state configuration is:

   [Kr] 5s² 4d¹⁰ 5p⁵