Chemistry for 8th grades

Chemical Formula

100

Nitrous Acid

HNO₂

200

Sulfur Trioxide

SO₃

300

Carbon Monoxide

CO

400

Magnesium Carbonate

MgCO₃

500

Dinitrogen Tetroxide

N₂O₄

Name of compound

100

CaCl₂

Calcium Chloride

200

SiC

Silicon Carbide

300

B₂O₃

Diboron Trioxide

400

HCl

Hydrochloric Acid

500

H₂SO₄

Sulfuric Acid

Popular chemistry questions

100

Which chemical element does not exist? 

a) Moscovium

b)Francium

c)Australium

c)Australium

200

The central part of the atom?

nucleus

300

The Periodic Table of Elements mirrors our model of the atom.  Each period in the periodic table represents what aspect of the atomic theory?

Each period represents an energy level in the electron cloud.

400

Which element has the largest atomic radius?

Francium

500

Why does electronegativity decrease as we go up a group in the periodic table?

1. Shielding Effect - There are fewer core electrons to shield the attractive force of the nucleus from the valence electrons.

or

2. There are fewer energy levels and the valence electrons are closer to the attractive force of the nucleus.

Popular chemistry questions2

100

True or false?

there are about 128 elements in periodic table

false 

there about 118 elements in periodic table

200

The smallest particle of matter

atom

300

Sodium has one type of atom,so it is an element or compound

an element

400

Rotates around the nucleus

a)proton

b)electron

c)neutron

b)electron

500

Define the term "solvent"

A solvent is any substance, usually liquid, which is capable of dissolving one or several substances

Non-Metals

100

Which non-metal has the highest electronegativity

Florine

200

The lightest non-metal

hydrogen

300

Explain why most metals have high melting points?

atoms held strongly

400

When Phosphorus forms an ion, what will be the charge of that ion?

-3

500

What is the only non-metal that is not a gas at room temperature?

Bromine