Which of the following is an isoelectronic series? f-, cl-, br-,i- o2- ,f- ,ne, na+ s, cl, ar, k si2- ,p2-, s2-, cl2-

The group of atoms which constitute an isoelectronic series are: O2- ,F- ,Ne, Na+

Definition:

An isoelectronic series refers to a group of atoms/ions with the same electron configuration.

The electron configuration of the atoms/ions in the isoelectronic series are as follows;

It is evident from above that the electron configuration of atoms/ions in the isoelectronic series are equal.

This is not the case in other group of atoms; As such, they are not isoelectronic.

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(b) O²⁻,F⁻ ,Ne, Na⁺

Explanation:

An isoelectronic series is a sequence of atoms/ions with the same electron configuration.

(a) F⁻, Cl⁻, Br⁻, I⁻

F⁻:   [He] 2s²2p⁵

Cl⁻:  [Ne] 3s²3p⁵

Br⁻: [Ar] 4s²4p⁵

I⁻:    [Kr] 5s²5p⁵

The ions all have different electron configurations. Not isoelectronic.

(b) O²⁻,F⁻ ,Ne, Na⁺

O²⁻: [Ne]

F⁻ :  [Ne]

Ne:  [Ne]

Na⁺: [Ne]

The species all have the same electron configuration. Isoelectronic.

(c) S, Cl, Ar, K

S:   [Ne] 3s²3p⁴

Cl: [Ne] 3s²3p⁵

Ar: [Ar]

K:  [Ar] 4s

The atoms all have different electron configurations. Not isoelectronic.

(d) Si²⁻ ,P²⁻, S²⁻-, Cl²⁻

Si²⁻: [Ne] 3s²3p⁴

P²⁻:  [Ne] 3s²3p⁵

S²⁻:  [Ar]

Cl²⁻: [Ar] 4s

The ions all have different electron configurations. Not isoelectronic.

answer: the primary difference between a hypothesis and a theory is that b hypothesis is falsifiable, but a theory has been proven to be correct. theory is an explanation of something that is happening but hypothesis is a guess of something that can happen

explanation:

1. for the first question, we must find the mass of the anhydrous salt, mgso₄. the molar mass for mgso₄·7h₂o is 246.47 g/mol, while that of mgso₄ is 120.37 g/mol.7.834 g mgso₄·7h₂o * 1 mol mgso₄·7h₂o/246.47 g * 1 mol mgso₄/1 mol mgso₄·7h₂o * 20.37 g mgso₄/mol = 0.647 g mgso₄

2. mass of water = mass of sample - mass of anhydrous salemass of water = 7.834 - 0.647 = 7.19 gpercent water in hydrate = 7.19/7.834 * 100 = 91.74%