Science 12.2

Matter is anything that has ______ and _________. All matter is made of tiny particles called atoms. 

• protons & electrons
• energy & bonds
• mass & volume. 
• solids & gas

All matter is made of tiny particles called atoms

• compounds
• molecules
• atoms
• volume

A ___________ is a substance composed of two or more different types of atoms

• compound
• mass
• molecule
• nuetron

A __________ is a unit of matter composed of two or more atoms held together by chemical bonds

• molecule
• volume
• proton
• neucleus

The idea of the atom was first proposed by the Greek philosopher ____________ in the fifth century B.C. 

• John Dalton
• Albert Einstein
• Dimitri Mendelov
• Democritus

During the early 1800s, a teacher named John Dalton further developed atomic theory. Dalton suggested that atoms of the same element had the same characteristics and properties. He defined properties as the way atoms behaved and reacted.

• Neils Bohr
• Democritus
• John Dalton
• Bill Nye

In the early 1900s, _______  ________ proposed that electrons traveled in circular orbits similar to the way planets orbit the sun.

• John Dalton
• Dimitri Mendelov
• Neils Bohr
• John Henry

The positive particles of an atom are 

• electrons 
• positrons 
• neutrons 
• protons 

the central region of an atom where its neutrons and protons are is its 

• nucleus 
• electron cloud
• core 
• center 

all matter is made of what 

• energy 
• atoms 
• electrons 
• compounds