History of Periodic Table

Front

What is the main contribution of Dmitri Mendeleev to the periodic table?

Back

He predicted the existence (and properties) of new elements.

Front

What is a periodic table?

Back

An arrangement of elements in columns based on their atomic number.

Front

What are neutrons?

Back

Particles in an atom's nucleus that are neutral and have no charge.

Front

What did John Dalton propose about atoms in 1805?

Back

All matter is made of atoms, and the atoms of a particular element are all identical.

Front

What is the difference between Mendeleev's table and the modern periodic table regarding transition elements?

Back

Mendeleev's table did not include transition elements.

Front

How are elements arranged in the modern periodic table?

Back

Elements are arranged according to their atomic number.

Front

What is the significance of gaps in Mendeleev's periodic table?

Back

Gaps indicated the existence of undiscovered elements.

Front

What is the 'law of triads' in chemistry?

Back

A principle that states that groups of three elements with similar properties can be arranged in order of increasing atomic mass.

Front

What are protons?

Back

Positively charged particles found in the nucleus of an atom.

Front

What is the atomic number of an element?

Back

The number of protons in the nucleus of an atom, which determines the element's identity.