Chemistry

Periodic Classification and Elements

1,092 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

Which is the lightest element in the universe?

  1. Helium

  2. Hydrogen

  3. Nitrogen

  4. Silicon
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Hydrogen is a chemical element. It is the simplest atom in the Universe. On a periodic table of the elements, hydrogen is on the top row, usually either on the left or on its own above the transition metals.

Multiple choice

The cause of periodicity is

  1. the increase in atomic number

  2. the increase in atomic mass

  3. the number of electrons in the valence shell

  4. the recurrence of similar outer most electronic configurations
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

The cause of periodicity is the recurrence of similar outer most electronic configurations.

Multiple choice

In a period, as we proceed from left to right

  1. the metallic character of elements increases

  2. the metallic character of elements decreases

  3. the metallic character does not changes

  4. the metallic character first decreases then increases
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

In a period, as we proceed from left to right, the metallic character of elements decreases. This is due to decrease in size and increase in the s- character.