Chemistry

Periodic Classification and Elements

1,176 Questions

Periodic classification organizes chemical elements based on atomic structure, periodic laws, and elemental properties. It covers historical classification systems, electron configurations, and periodic trends. Test takers preparing for chemistry sections will find these questions crucial for mastering fundamental element properties and atomic interactions.

Periodic table structureAtomic orbitalsElement identificationPeriodic laws

Periodic Classification and Elements Questions

Multiple choice

Atoms of which of the following elements exist independently?

  1. Hydrogen

  2. Nitrogen

  3. Helium

  4. Oxygen
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Helium is a noble gas, which means its outer electron shell is full, making it stable enough to exist as a single atom. Hydrogen, nitrogen, and oxygen typically exist as diatomic molecules.

Multiple choice

Nuclear atom is also known as

  1. ligand

  2. complex ion

  3. co-ordination sphere

  4. central metal atom or ion

Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

A complex ion contains a metal atom or ion known as the central metal atom or ion. It is sometimes also called a nuclear atom.

Multiple choice

Helium is a noble gas.It is placed in __________.

  1. the s-block

  2. the p-block

  3. the d-block

  4. the f-block
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

The s-block of the periodic table of elements consists of the first two groups: the alkali metals and alkaline earth metals, plus hydrogen and helium.These elements are distinguished by the property that in the atomic ground state, the highest energy electron is in a s-orbital. Except in hydrogen and helium, these electrons are very easily lost to form positive ions.