Embedded Files
"What are atoms and how do they work??"
Matter: is anything that has mass and takes up space!
All matter is made up of atoms.
Atoms have a dense middle part called a nucleus and a big empty (mostly) space that surrounds it called the electron cloud.
Most of the mass is in the nucleus of an atom. Two main sections of an atom include:
Nucleus: Protons (+ charge) and Neutrons (no charge)
Electron cloud: Electrons (- charge) but is mostly empty space. Changes in the number of electrons are responsible for almost all chemical changes!
BONDING
Atoms like to have a specific number of electrons in their electron clouds. This is why some types of atoms are more more reactive than others. The problem is, when this happens it changes the charge of the atom and atoms also like to be neutral in charge. When an atom has a charge it helps balance itself by hooking up with another atom (or maybe even 2 or three other atoms!) of an opposite charge.
When atoms "hook up" or "hold hands" this is called a bond. A bond results from the sharing of two electrons between atoms (this sharing is like the glue that holds atoms together to make molecules.
Electrons weigh nearly nothing so we don't count them in the total mass of an atom.
Protons and Neutrons account for 9.99999% of the mass. Each proton or neutron weighs 1amu (atomic mass unit).
Atomic Number = # Protons + # Neutrons
Electrons (in a neutral atom) = # Protons
Ions & Charge Balancing:
Atoms want to be neutral in charge. This means a that # of electrons (-) must equal # protons (+)
If you have more protons than electrons the atom overall becomes positive.
If you have more electrons than protons the atom overall becomes negative.
In either case, the resulting charged atom is called an ion.
The northern lights is an example of ions in our atmosphere:
H2O is the formula for water means that there are two hydrogen atoms attached to an oxygen molecule (left).
The atoms in a water molecule form covalent polar bonds.
Find more about water on the properties of water page!
Important vocabulary from this section:
- Matter
- Atom:
- Electron
- Proton
- Neutron
- Atomic Number
- Atomic Mass
- Molecule
- Ion
- Bond
- Covalent
- Polar-Covalent
Above: Northern Lights. Ions burning up at the magnetic poles of earth and emitting colorful light. The different colors belong to the different types of atoms with different charges.
Back to:
Biology // Biology Resources
Report abuse