There are over 100 different elements, which are made up of atoms. Elements can be divided into metals and non-metals. Chemical symbols and formulae are used to represent elements and compounds.
Which of these is the smallest particle?
A speck of dust
Which of these is the correct symbol for magnesium?
Which statement about atoms and molecules is correct?
Elements always exist as separate atoms
Elements always exist as pairs of atoms called molecules
Elements and compounds can exist as molecules
How many different atoms are there in a compound?
Two or more
Approximately how many elements are there?
Which one is a compound?
Which of these contains two carbon atoms and six hydrogen atoms?
Which of these contains four hydrogen atoms?
How many atoms are there in total in a molecule of sulfur trioxide, SO3?
Why does air not have a definite formula?
It contains different amounts of water depending on where you are
It depends on the temperature
It is not a compound