The number of electrons in the last shell of krypton are ____.

Correct! Wrong!

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Krypton has 8 electrons in its last shell.

Chlorine molecule is a ____.

Correct! Wrong!

A molecule of chlorine is made up of two atoms of chlorine (Cl 2), hence it is diatomic.

The electronic configuration of an element with atomic number 12 is____.

Correct! Wrong!

The electronic configuration of an element with atomic number 12 is 2, 8, and 2.

The N-shell can accommodate a maximum of 32 electrons.

Correct! Wrong!

The maximum numbers of electrons that can be accommodated in the N-shell (fourth shell) are 32.

7N14 and 7N15 represents ____.

Correct! Wrong!

Isotopes have same atomic number but different mass number. As 7N14 and 7N15 have same atomic number, they are isotopes.

What is the valency of phosphate ion?

Correct! Wrong!

Phosphate is a trivalent ion. Therefore, its valency is 3.

The compounds are formed by combination of atoms. This law was stated by ____.

Correct! Wrong!

According to Dalton's atomic theory, the compounds are formed by the combination of atoms.

The number of protons in an atom X, with atomic number Z and mass number A are ____.

Correct! Wrong!

The numbers of protons in an atom X of atomic number Z is Z, since, the number of protons is equal to the atomic number (Z) of an atom.

An isotope of ____ is used in the treatment of cancer.

Correct! Wrong!

The isotope of cobalt (Co-60) is used in the treatment of cancer.

Atoms of different elements have the same mass.

Correct! Wrong!

According to Dalton’s atomic theory, atoms of different elements have different masses.

The valency of nitrogen in ammonia is ____.

Correct! Wrong!

Ammonia is formed when one atom of nitrogen combines with three atoms of hydrogen. Therefore, the valency of nitrogen in ammonia is three.

The indivisibility of atom was proposed by ____.

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According to Dalton’s atomic theory, an atom cannot be created, divided, or destroyed as a result of a chemical change.

The number of valence electrons in neon atom are ____.

Correct! Wrong!

In neon atom there are 8 valence electrons.

Atomicity of sulphur is ____.

Correct! Wrong!

Atomicity of sulphur is 8. Therefore, sulphur is octa atomic.

The number of atoms present in a molecule of an element is called ____.

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Atomicity is defined as the number of atoms present in one molecule of an element.

The elements present in quick lime are ____.

Correct! Wrong!

The elements present in quick lime are calcium and oxygen, it is calcium oxide and its formula is CaO .

The symbol of chromium is ____.

Correct! Wrong!

The symbol of chromium is Cr.

A molecule is made up of atoms.

Correct! Wrong!

A molecule is formed by the chemical combination of two or more atoms of same or different elements.

Which of the following atoms do not have neutrons?

Correct! Wrong!

Hydrogen atom has no neutrons. It has 1 electron and 1 proton.

Which of the following element forms a triatomic molecule?

Correct! Wrong!

Ozone is a triatomic molecule of oxygen. In one molecule of ozone, there are three oxygen atoms.

Oxygen combines with hydrogen to form water and hydrogen peroxide. This is in accordance with ____.

Correct! Wrong!

According to law of multiple proportions, when two elements combine, the ratio in which one of the elements combines with a fixed weight of the other element is a simple whole number ratio.

The electronic configuration of oxygen atom is ____.

Correct! Wrong!

The atomic number of oxygen is 8. Therefore, the electronic configuration of oxygen atom is 2, 6.

Modern atomic symbols are based on the method proposed by ____.

Correct! Wrong!

A Swedish chemist Berzelius introduced the first universally acceptable system of atomic symbols.

What is the name of the compound represented by the formula CaCO3?

Correct! Wrong!

Ca is the symbol of calcium and CO32− is a carbonate radical, hence, the name of the compound is calcium carbonate.

Isotopes are ____.

Correct! Wrong!

Isotopes are atoms of same element having same atomic number but different mass number.

ICSE Class 9th Chemistry 1 - The language of chemistry MCQs
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