elements and the periodic table

Question 1

Compound

Answer 1

A substance made up of two or more elements chemically combined

Question 2

Element

Answer 2

A substance which cannot be broken into simpler substances by chemical means

Question 3

Elements are composed of

Answer 3

atoms

Question 4

Atoms have a

Answer 4

nucleus and electrons.

Question 5

Protons and neutrons are in the

Answer 5

nucleus

Question 6

Triads

Answer 6

group of 3 elements with similar chemical properties where atomic weight of the middle element is ~equal to average of other two.

Question 7

Modern periodic table

Answer 7

an arrangement of elements in order of increasing atomic number

Question 8

Modern Periodic Law

Answer 8

when elements are arranged in order of increasing atomic number, the properties of the elements vary periodically.

Question 9

Mendeleev

Answer 9

gaps
Some undiscovered
Increasing atomic weight
Transition elements included with other elements
Order increasing atomic weight

Question 10

Modern

Answer 10

No gaps
More elements
Increasing atomic number
Transition elements in separate block
Order increasing atomic number

Question 11

Defined elements as substances that could not be broken into simpler substances.

Answer 11

Robert Boyle