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Question 1

John Dobereiner developed the law of triads

Answer 1

1829

Question 2

Law of octaves discovered by John Newlands

Answer 2

1863

Question 3

March 6th, 1869

Answer 3

Dmitri Mendeleev discovered that periodic pattern didn’t apply to heavier elements and left spaces for other elements.

Question 4

1913

Answer 4

Henry Mosley discovered that atomic number should be used to order elements.

Question 5

450 BC

Answer 5

“All matter around us is made of invisible tiny particles- atomos”

Question 6

1803

Answer 6

Dalton’s atomic theory

Question 7

1909

Answer 7

Ernest Rutherford’s Nucleus theory-
• Positive charge is concentrated in the nucleus
• Most of the Atom is empty space

Question 8

Henry Mosely discovered each element has a unique number of protons.

Answer 8

1887—1915

Question 9

1911

Answer 9

Niels Bohr– Bohr‘s orbit model
• Electrons orbit the nucleus
• Energy of the electrons is quantised

Question 10

How do you calculate atomic mass?

Answer 10

The sum of the proton number and neutron number

Question 11

How many neutrons does carbon-14 contain?

Answer 11

8

Question 12

Before the discovery of the _______, atoms were thought to be tiny spheres that could not be divided.

Answer 12

Electrons

Question 13

What is the approximate size of an atoms radius?

Answer 13

1 x 10^-10