How can we help?
You can also find more resources in our
Select a category
Something is confusing
Something is broken
I have a suggestion
What is your email?
What is 1 + 3?
Atoms, Elements and Compounds
a subatomic particle that has a positive charge and that is found in the nucleus of an atom
a subatomic particle that has no charge and that is found in the nucleus of an atom
negatively charged particle; located outside the atomic nucleus
Russian chemist who developed a periodic table of the chemical elements and predicted the discovery of several new elements (1834-1907)
the number of protons in the nucleus of an atom
total mass of the protons and neutrons in an atom, measured in atomic mass units
Positively Charged Atom
more protons than electrons
Negatively Charged Atom
more electrons than protons
any of the chemically inert gaseous elements of the helium group in the periodic table
when CO2 is mixed with lime water, it makes calcium carbonate (blew through straw into lime water, gave off CO2) and the limewater turns milky- proving the existence of CO2
Identifies common lab gases (O2) by inserting a glowing wooden splint into a test tube with unknown gas
The captured gas is lit and if it makes a 'pop' sound then it is known to be hydrogen gas