If the following elements were to form ions, they would attain the same number of electrons as which noble gas?
elements: as, s, na, rb
noble gas: he, ne, ar, kr

To work his question use the periodic table. There you can find any element. Its position on the table will tell you easily which configuration it will reach after losing or gaining electrons.

An neutral element has the same number of electrons (negative particles) and protons (positive particles). That is why it is neutral: negative charge = positive charge ==> zero net charge.

If an element gain electrons it will have an excess of negative charge (because the number of protons has not changed), forming what is known as an anion (a negative ion). If an element lose electrons it will have an excess of positive charge, forming a cation (a positive ion).

Then electronic configuration is the clue respond this question.

You need to use the periodic table.

1) As

It is the element number 33. It is in the group 15.

There are in total 18 groups. The noble elements are in the group 18.

When As, which is a non metal, gain 3 electrons (15 + 3 = 18) it will become an anion (negative ion) with the same number of electrons than the noble gas that is three places to its right in the periodic talbe, which is Kr.

The non metals only form cations, this is they only can gain electrons.

2) S

It is also a non metal.

It is in the group 16 of the periodic table. When it gains two electrons (16 +2 = 18) it will become a negative ion (anion) with the same number of electrons than the noble gas two places to its righ in the periodic table, Ar.

3) Na

It is an alkalyne metal. Alkalyn metals are in the group 1 and row 3. Which means that they have only one electron in its valence shell. These elements can lose this valence electron to have the same number of electrons of the noble gas that is immediately before it (one row over it but in the group 18). In this case, that noble that is in the row 2 and group 18; it is Ne.

4) Rb is another alkalyne metal (group 1). It is in the row 5. Rb can lose its electron from the valence shell to become a cation (positive ion) with the same number of electrons than the noble gas (group 18) of the previous row (i.e. 4). The noble gas in the row 4 is Kr.

The As element is closest to the configuration of element Kr

The S element is closest to the configuration of the Ar

The element Na is closest to the configuration of the element Ne

The Rb element is closest to the configuration of the element Kr

Further explanation

Atoms have different stability. Unstable atomic atoms will try to form stable electron configurations like those of noble gases. Where noble has the number of outer electrons 2 or 8

The formation of electron configurations can be done by forming shared ions or electron pairs

Metal elements have low ionization energy  (easily release electrons) forms cation and non-metallic elements have a high electron affinity  (easily pulling electrons) that form anions

The location of the element group in the periodic system is determined by the number of valence electrons that fill the last sub-skin

The element period is determined from the valence shell (the largest main quantum number (n))

The chemical element group is divided into two, namely:

Group A, occupies sub skins s and p

Group B, occupies sub skin d

The electron configuration of noble gases is:

He: 1s ²

Ne: [He] 2s² 2p⁶

Ar: [Ne] 3s² 3p⁶

Cr: [Ar] 3d¹⁰ 4s² 4p⁶

Let's look at the answer choices

A. As

Electron configuration

[Ar] 3d¹⁰ 4s² 4p3³

The As element is closest to the configuration of element Kr by binding 3 electrons to be stable, becoming As³⁻

B. S

Electron configuration

[Ne] 3s² 3p⁴

The S element is closest to the configuration of the Ar element by binding 2 electrons to be stable, becoming S²⁻

C. Na

Electron configuration

[Ne] 3s¹

The element Na is closest to the configuration of the element Ne by releasing 1 electron to be stable, becoming Na⁺

D. Rb

Electron configuration

[Kr] 5s¹

The Rb element is closest to the configuration of the element Kr by releasing 1 electron to be stable, becoming Rb⁺

Learn more

chemical bond holds the Na⁺ and Cl⁻ ions

link

Identify the group number

link

ionic bonding

link

Keywords: noble gas, stable, electron configuration