Question

Identify each of the following elements: (a) a halogen whose anion contains 36 electrons, (b) a radioactive noble gas with 86 protons, (c) a Group 6A element whose anion contains 36 electrons, (d) an alkali metal cation that contains 36 electrons, (e) a Group 4A cation that contains 80 electrons.

Answer 1

The halogen whose anion contains 36 electrons is Krypton. The radioactive noble gas with 86 protons is Radon. The Group 6A element whose anion contains 36 electrons is Selenium.

Step-by-step explanation:

(a) The halogen whose anion contains 36 electrons is Krypton. Krypton has an atomic number of 36, so it contains 36 electrons in its neutral state. When it forms an anion, it gains one electron, resulting in a total of 36 electrons in the anion.

(b) The radioactive noble gas with 86 protons is Radon. Radon has an atomic number of 86, which means it has 86 protons. It is radioactive because it has an unstable nucleus and undergoes radioactive decay.

(c) The Group 6A element whose anion contains 36 electrons is Selenium. Selenium has an atomic number of 34, so it normally contains 34 electrons. When it forms an anion, it gains two electrons to achieve a stable electron configuration with 36 electrons in its outermost shell.

(d) An alkali metal cation that contains 36 electrons is Caesium. Caesium has an atomic number of 55, so it normally contains 55 electrons. However, when it loses one electron to form a cation, it now contains 36 electrons.

(e) A Group 4A cation that contains 80 electrons is Lead. Lead has an atomic number of 82, so it normally contains 82 electrons. When it loses two electrons to form a cation, it now contains 80 electrons.

Answer 2

For a: The correct answer is
`Br^-`

For b: The correct answer is Radon.

For c: The correct answer is
`Se^(2-)`

For d: The correct answer is
`Rb^+`

For e: The correct answer is
`Pb^(2+)`

Step-by-step explanation:

An ion is formed when an atom looses or gains electron.

When an atom looses electrons, it will form a positive ion known as cation.

When an atom gains electrons, it will form a negative ion known as anion.

Atomic number is defined as the number of protons or electrons that are present in a neutral atom.

Atomic number = number of protons = number of electrons

Atomic mass is defined as the sum of number of protons and neutrons that are present in an atom.

Atomic mass = Number of protons + Number of neutrons

• For a:

Halogens are Fluorine (Z = 9), Chlorine (Z = 17), Bromine (Z = 35), Iodine (Z = 53) and Astatine (Z = 85)

Bromine is the 35th element of the periodic table having electronic configuration
`[Ar]3d^(10)4s^24p^5`

This element will gain 1 electron and will form
`Br^-` ion.

The ion formed has 36 electrons.

• For b:

Noble gas having 86 protons means the element having atomic number 86 is Radon.

Thus, the correct answer is Radon.

• For c:

Group 6A elements are Oxygen (Z = 8), Sulfur (Z = 16), Selenium (Z = 34), Tellurium (Z = 52) and Polonium (Z = 84)

Selenium is the 34th element of the periodic table having electronic configuration
`[Ar]3d^(10)4s^24p^4`

This element will gain 2 electrons and will form
`Se^(2-)` ion.

The ion formed has 36 electrons.

• For d:

Alkali metals are Lithium (Z = 3), Sodium (Z = 11), Potassium (Z = 19), Rubidium (Z = 37), Cesium (Z = 55) and Francium (Z = 87)

Rubidium is the 34th element of the periodic table having electronic configuration
`[Kr]5s^1`

This element will loose 1 electron and will form
`Rb^(+)` ion.

The ion formed has 36 electrons.

• For e:

Group 4A elements are Carbon (Z = 6), Silicon (Z = 14), Germanium (Z = 32), Tin (Z = 50) and Lead (Z = 82)

Lead is the 82th element of the periodic table having electronic configuration
`[Xe]4f^(14)5d^(10)6s^26p^2`

This element will loose 2 electrons and will form
`Pb^(2+)` ion.

The ion formed has 80 electrons.