The Periodic Table- Development of Periodic Table

Question 1

Before the discovery of protons, electrons and neutrons, scientists ordered the elements by their ______ ______.

Answer 1

Before the discovery of protons, electrons and neutrons, scientists ordered the elements by their atomic weight.

Question 2

__________ placed elements in more appropriate places, grouping elements with similar __________ so patterns could be seen. This meant he sometimes left gaps or changed the order of ______ ______.

Answer 2

Mendeleev placed elements in more appropriate places, grouping elements with similar properties so patterns could be seen. This meant he sometimes left gaps or changed the order of atomic weight.

Question 3

Elements with properties Mendeleev predicted were ___________ and filled the gaps.

Answer 3

Elements with properties Mendeleev predicted were discovered and filled the gaps.

Question 4

The elements on the modern _________ _____ are arranged in order of ___________ atomic number.

Answer 4

The elements on the modern periodic table are arranged in order of increasing atomic number.

Question 5

Elements are arranged in columns called ______ (going down) on the periodic table.

Answer 5

Elements are arranged in columns called groups (going down) on the periodic table.

Question 6

The number of electrons in the _________ _____ of an atom is the same as its _____ on
the periodic table.

Answer 6

The number of electrons in the outermost shell of an atom is the same as its group on
the periodic table.