Atomic Structure & Scientists

Front

What did Rutherford discover about the atom?

Back

Rutherford found that the atom is mostly empty space.

Front

What is the identity of the element with isotopes having masses of 75.23 amu (24.1%), 74.61 amu (48.7%), and 75.20 amu (27.2%)?

Back

The identity of the element is Arsenic (As).

Front

Who was the Greek philosopher that introduced the concept of 'atomos'?

Back

Democritus introduced the concept of 'atomos'.

Front

What element is represented by the atomic model shown?

Back

The element is Sodium (Na).

Front

Calculate the average mass of an element with isotopes having masses of 75.23 amu (24.1%), 74.61 amu (48.7%), and 75.20 amu (27.2%).

Back

The average mass is 74.92 amu.

Front

What is the main contribution of John Dalton to atomic theory?

Back

John Dalton proposed that all matter is made of atoms, which are indivisible and indestructible.

Front

What did J.J. Thomson discover about the atom?

Back

J.J. Thomson discovered the electron and proposed the 'plum pudding' model of the atom.

Front

What is the significance of the atomic number?

Back

The atomic number represents the number of protons in an atom and determines the element's identity.

Front

What is an isotope?

Back

Isotopes are atoms of the same element that have the same number of protons but different numbers of neutrons.

Front

What is the mass number of an atom?

Back

The mass number is the total number of protons and neutrons in an atom's nucleus.