What Is The Charge Of Selenium In H2Se, SeO2, SeO4, And SeS2?

At first guess, you could call selenium a metal that will form a cation. On the contrary, selenium is a metalloid and can carry either a positive or negative charge, depending on the compound it forms.

When selenium forms an anion, it bears a negative charge. When it forms a cation, it bears a positive charge. The most common selenium ion is the selenide ion, S2-.

Does selenium have an exact charge? Why does it exhibit multiple charges? Read this article to find out.

Properties of selenium

  • Selenium is a metalloid with more nonmetallic properties
  • It shares similarities with sulfur, tellurium, and arsenic
  • Selenium has an atomic number of 34 and an atomic weight of 78.96
  • It is a rare compound that is usually found in combination with heavy metals such as copper, mercury, lead, and silver. It is also found in combination with native sulfur and sometimes, by itself
  • Furthermore, selenium is a p-block element with electronic configuration [Ar] 3d10 4s2 4p4
  • Selenium exists as a solid and is strongly acidic
  • Selenium exhibits varying oxidation states such as -2, +4, and +6
  • In its amorphous form, it has a density of 4.28 grams/cm3 and 4.79 grams/cm3 in its gray form
  • In addition, selenium has a boiling point of 1,265°F (685°C) and melting points of 122°F(50°C) and 423°F(217°C) for the amorphous and gray selenium respectively

What is the charge of selenium?

Selenium is a neutral atom with no charge until it gains or losses electrons. Selenium gains two electrons to complete its octet structure and forms selenide, Se2-. This is the more common charge it exhibits.

In some other reactions, selenium will lose four of its valence electrons and form Se4+. This selenium ion is not as common as the -2 ion.

Does selenium have multiple charges?

Yes, it does. Selenium tends to exhibit two charges, -2 and +4, in different compounds. When it gains two electrons to attain stability, it forms a selenide ion, Se2-.

Also, in some reactions, it loses four of its valence electrons and becomes a cation, Se4+. However, Se2- is the most common selenium ion.

What is the charge of Se in SeO2?

The charge of Se in SeO2 is +4.

In a mathematical expression,

Se + 2(-2) = 0, -2 is the charge on the oxygen atom

Se – 4 = 0

+4 = Se

What is the charge of selenium in hydrogen selenide?

In hydrogen selenide, H2Se, the overall charge of the compound is 0, and the oxidation state of H is +1.

2(1) + Se = 0

2 + Se = 0

Se = -2

Therefore, the charge of Se in H2Se is -2.

What is the charge of selenium in selenium disulfide?

Selenium naturally has a -2 charge when it forms ions. However, in selenium disulfide, SeS2, Se exhibits a +4 charge.

Se + 2(-2) = 0

Se – 4 = 0

0+4 = Se

Se = +4

What is the charge of selenate?

The charge on selenate, SeO42-, is -2. Selenate readily reacts with sodium to form Na2SeO4, a weak oxidizing agent.


Is selenium a cation or anion?

Selenium forms an anion with a -2 charge. The selenium atom has 34 electrons with 6 electrons in its outermost shell. To attain the octet structure, it gains two more electrons and gets a negative charge.

What is the nuclear charge of selenium?

The nuclear charge of selenium is the same as its atomic number which is 34. The nuclear charge is the total charge on the nucleus

Is selenate an anion?

Yes, selenate, SeO42-, is an anion with a -2 charge. Its chemical structure and formula are analogous to that of sulfates.


Selenide, Se2-, is the most common selenium ion. But it also exists as a cation with a +4 charge. Selenium exhibits different charges in different compounds. This is owing to its ability to exhibit various oxidation states.

You should also learn how to calculate the Zeff, effective nuclear charge, of atoms.

Thanks for reading.

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