Moseley - Atomic Number

Question 1

What did Moseley study?

Answer 1

He studied the frequencies of the X-rays emitted by atoms of the different elements. He found that the frequencies varied with the quantity of positive charge in the nucleus.

Question 2

What did Moseley dicover?

Answer 2

He discovered a method of determining the number of protons in the nucleus of an atom. This number is called the atomic number

Question 3

Define atomic number

Answer 3

The atomic number of an atom is the number of protons in the nucleus of that atom

Question 4

Summarise Moseley’s work (3)

Answer 4

1. Moseley showed that if the elements are arranged in order of increasing atomic number, it is not necessary to reverse the order of some elements as Mendeleev had to do.
2. His studies showed that Mendeleev had been correct in placing tellurium before iodine.
3. He showed that by arranging the elements in order of increasing atomic number the elements fall naturally into the correct groups.

Question 5

Define the modern periodic table

Answer 5

The modern Periodic Table is an arrangement of elements in order of increasing atomic number

Question 6

Define Modern Periodic Law

Answer 6

When elements are arranged in order of increasing atomic number, the properties of the elements recur periodically, i.e. the properties displayed by an element are repeated at regular intervals in other elements

Question 7

To conclude, what did Mosley’s work do in relation to Mendeleevs?

Answer 7

It confirmed the position of the elements