Review-Matter

Scandium atoms have an atomic number of 21 and atomic mass of 45. What is NOT true about Scandium atoms?

• It has 24 neutrons.

• A neutral atoms has 21 protons and 21 electrons.

• It has 21 neutrons.

• It has 21 protons.

What is the atomic number of the atom shown in the picture?

• 13

• 14

• 1

• 27

What is NOT true about Iron?

• Fe is the chemical symbol.

• The atomic mass is 26.

• The atomic number is 26.

• It has 30 neutrons.

Which element is most likely to be a semi-conductor?

• B

• F

• Li

• H

An atom is neutral if:

• it has the same number of protons and neutrons.

• it has the same number of protons and electrons.

• it has an even number of valence electrons.

• it has the same number of electrons and neutrons.

Elements are made of 

• many types of atoms 
• the periodic table
• one type of atom 
• molecules 

A proton is described as

• a positively charged particle in the nucleus

• a positively charged particle in the rings of an atom

• a neutrally charge particle in the nucleus

• a negatively charge particle in the nucleus

What does the atomic number represent?

• # of protons and neutrons in the nucleus

• # of neutrons in the nucleus

• # of protons in the nucleus

• # of electrons in the orbit

A pure substance made of only one kind of atom

• atom

• element

• molecule

• nucleus

A mixture that is not uniform in composition; components are not evenly distributed throughout the mixture

• homogeneous mixture

• solution

• heterogeneous mixture

• colloid