Elements Symbols
Atomic Structure
Periodic Table Basics
Counting Atoms
Bohr's Atomic Model
100

He

Helium

100

Which particle has a positive charge?

Proton

100

How many periods are in the periodic table?

7

100

How many atoms are in O2 ?

2

100


What is the atomic number of this atom?

2

200

P

Phosphorus

200

Which particle that has no charge?

Neutron

200

The atomic number is the number of ___ in the atom's nucleus.

Protons 

200

How many atoms of each element are in NaCl?

Na=1, Cl=1

200

What is the mass number of this atom?

7

300

Fe

Iron

300

Which particles make up the nucleus of an atom?

Protons and Nucleus 

300

Elements in the periodic table are listed in order of their ___.

Atomic Number 

300

HCl has how many atoms of each element?

H=1, Cl=1

300

What element is this?

Nitrogen

400

Au

Gold

400

What does the atomic number represent? 

The number of protons or electrons

400

The number found below the chemical name is the ___.

Atomic Mass 

400

How many elements are in this compound?... NaHCO3

4

400

What element is represented in this Bohr Model?

Lithium

500

K

Potassium

500

What is the atomic mass for helium? 

500

How many groups make up the periodic table?

18

500

4 NaCl represents several molecules of table salt. How many atoms of chlorine are present in this example?

4

500

An atom has an atomic number of 15 and a mass number of 31. How many protons are there in the atom?  

15