Atomic History
States of matter
Chemical formulas
Lewis dot structure
The pH scale
100

Who first proposed atoms?

Democritus

100

What are the three states of matter?

Solid liquid and gas

100

What is H₂O?

Water

100

What are Lewis dot structures?

it shows valence electrons

100

What is pH a measure of?

Acidity or basicity of a solution

200

Who made the plum pudding model?

J.J. Thomson

200

What state of matter has a definite shape?

Solid

200

What are chemical formulas?

A chemical formula is an expression that shows the elements in a compound.

200

How many valence electrons does oxygen have?

6


200

pH of pure water?

7

300

Who discovered the nucleus?

Ernest Rutherford

300

What state of matter takes the shape of its container?

Liquid

300

How many atoms are in CO₂?

3 atoms

300

Draw the Lewis structure of H₂O

O in center 2 bonds to H 2 lone pairs

300

Is lemon juice acidic or basic?

acidic

400

Who proposed electrons move in orbits?

Niels Bohr  

400

What happens to a solid when it melts?

becomes a liquid

400

What is the difference between CO and CO₂?

CO has one oxygen atom and CO₂ has two oxygen atoms

400

How many lone pairs are in the Lewis dot structure of NH₃?

One lone pair

400

pH of a strong base like NaOH?

Around 13-14

500

What did James Chadwick discover?

Neutron

500

what is a plasma?

A state with charged particles

500

What is the molar mass of H₂O?

18 g/mol

500

Why is CO₂ linear in Lewis structure?

Carbon has 2 double bonds and no lone pairs

500

Why does vinegar have a low pH?

Because it has many hydrogen ions