PAX PAX Chemistry and Physical Science 1

Question 1

What is the atomic number of an element?

Accepted Answer

The number of protons in the nucleus

Answer

The atomic number equals the number of protons in an atom's nucleus and identifies the element.

Question 2

What type of bond is formed when electrons are shared between atoms?

Accepted Answer

Covalent bond

Answer

A covalent bond forms when two atoms share electrons to achieve a stable configuration.

Question 3

What is the pH of a neutral solution?

Accepted Answer

7

Answer

A neutral solution, such as pure water, has a pH of 7; below 7 is acidic and above 7 is basic.

Question 4

Which state of matter has a definite volume but no definite shape?

Accepted Answer

Liquid

Answer

Liquids have a definite volume but take the shape of their container because their molecules can flow.

Question 5

What is the chemical formula for water?

Accepted Answer

H₂O

Answer

Water is composed of two hydrogen atoms bonded to one oxygen atom, giving it the formula H₂O.

PAX Exam Practice Test