Atoms & Subatomic Particles
What are the tiny particles that make up all matter?
Atoms
What is the chart that organises all known chemical elements called?
The periodic table
What is one single particle of matter called?
An atom
What does a subscript tell us in a chemical formula?
How many atoms of that element there are
Electrons are arranged around the nucleus in what?
Electron shells
Name the three main subatomic particles.
Protons, neutrons and electrons
What does the atomic number tell us?
The number of protons in an atom
What is a pure substance made from only one type of atom called?
An element
If there is no subscript after an element, what number does it mean?
1
How many electrons can the first shell hold?
2 electrons
Which two subatomic particles are found in the nucleus?
Protons and neutrons
Carbon has an atomic number of 6. How many protons does it have?
6 protons
What is two or more atoms chemically bonded together called?
A molecule
In H₂O, how many hydrogen atoms and oxygen atoms are there?
2 hydrogen atoms and 1 oxygen atom
What is the electron shell pattern for the first 20 elements?
2, 8, 8, 2
Which particle has a negative charge, what is the approximate mass?
Electron, zero
In a neutral atom, the number of electrons is equal to what?
The number of protons
What is a substance made from two or more different elements chemically bonded together called?
A compound
In C₆H₁₂O₆, how many atoms are there altogether?
24 atoms altogether
Oxygen has 8 electrons. What is its electron configuration?
2, 6
What are the mass and charge of a proton, neutron and electron?
Proton = mass 1, charge +1. Neutron = mass 1, charge 0. Electron = mass ≈0, charge -1.
Why is atomic mass often a decimal instead of a whole number?
Because it is the average mass of different isotopes of that element.
Why is O₂ a molecule but not a compound?
Because it has two atoms bonded together, but they are both oxygen, so there is only one element.
What does the big number in front mean in 2H₂O?
It means there are 2 water molecules.
Magnesium has an atomic number of 12. What is its electron configuration?
2,8,2