The atom

Question 1

What is an atom?

Answer 1

Smallest unit of matter that has the properties of an element.

Question 2

The Atomic Theory

Answer 2

• Published in 1807 by John Dalton.
• All matter is made up of atoms.
• Atoms of the same element have the same mass¨ and properties.
• compounds are combinations of 2 or more different atoms.
• a chemical reaction is a rearrangement of atoms.

Question 3

Planetary model

Answer 3

• Proposed by Bohr.
• Electrons can only exist in fixed orbits or energy levels.
• These energy levels are at specific distances from the nucleus.

Question 4

Quantum model

Answer 4

• Proposed by Schrödinger.
• States that it is impossible to know exactly the position of an electron.
• You are more likely to find electrons towards the center.

Question 5

Solid-sphere model

Answer 5

• Proposed by Dalton.

* Indestructible tiny sphere.

Question 6

Plum pudding model

Answer 6

• Proposed by J.J Thomson

* Included the existence of electrons.

Question 7

Nuclear model

Answer 7

• Proposed by E. Rutherford
• All positively charged particles of the atom are in the nucleus, all negatively charged electrons were scattered outside the nucleus