Atomic Structure

What is the smallest part of an element that can still be identified as an element?

• compound

• nucleus

• atom

• mixture

More than 2000 years ago a Greek philosopher named Democritus suggested the idea of an atom. The Greek word “Atomos” means

• can’t be divided

• periodic table

• almost mixed

• not yet discovered

Tags

NGSS.MS-PS1-1

In 1803 John Dalton proposed the “Atomic Theory of Matter” which states

• All the these are true

• All elements are made of atoms

• Atoms from the same element are the same

• Atoms from different elements are different

• Atoms cannot be created or destroyed

Tags

NGSS.MS-PS1-5

A negatively charged particle found outside the nucleus of the atom is a(n) ___________.

• electron

• proton

• neutron

• atomic mass

A neutral particle found in the nucleus of the atom is a(n) ___________.

• electron

• proton

• neutron

• molecule

A positively charged particle found in the nucleus of the atom is a(n) ___________.

• electron

• proton

• neutron

• isotope

The total number of protons and neutrons in an atom is called its ___________.

• atomic mass

• atomic number

• matter

• electron cloud

What is an atom of an element with the same number of protons but different number of neutrons called?

• electron

• proton

• neutron

• isotope

Where would you expect to find an atom’s electrons?

• nucleus

• electron cloud

• in a mixture

• only in isotopes

How many electrons can the first energy level of an atom hold?

• 2 electrons

• 8 electrons

• 18 electrons

• 32 electrons