Study the solutions in the glasses. put the solutions in order from concentrated to dilute.
a.

1, 2, 3

b.
1, 3, 2

c.
3, 1, 2

d.
2, 3, 1

Ithink it’s 3 as the answer.

Yes you are correct use the scientific method

Order of filling levels and sublevels of electrons: 1s²2s²2p⁶3s²3p⁶4s²3d¹⁰4p⁶5s²4d¹⁰5p⁶6s²3f¹⁴5d¹⁰6p⁶for an element with 5 electrons in the 3d energy level: full configuration: 1s²2s²2p⁶3s²3p³.