Chemistry Flashcards
Fundamentals of chemistry
Atoms
Definition + components
The most basic unit of all matter. Neucleus surrounded by subatomic particles.
Subatomic particles
List them
- Protons
- Neurons
- Electrons
Protons
charge / mass / location on atom
Subatomic particle
+1 charge / 1 mass / stuck in the in nucleus
* Number dictates it’s element
Electrons
Subatomic particle
-1 charge / «<1=0 / travels around the nucleus
- moves easily between atoms
- charge changes when added or removed
Neurons
Subatomic particle
0 charge / 1 mass / stuck in the nucleus
What is the charge of an atom?
protons - electrons
= charge
What is the mass of an atom?
of protons - # of neurons
= mass
What are elements?
Different types of atoms that have different chemical properties.
The # of protons determines what element an atom is and the charge of its nucleus.
The # of neurons and electrons can be different between different atoms of the same element.
Periodic table of elements
Table that shows all elements known to man, each square is a different element.
Contains:
* Name of element (not always)
* Atomic # = # of protons in the nucleus
* Atomic symbol = 1 capital letter or 1 capital + 1 lower case
* Atomic mass = mass of atom, #protons + #neurons
Electron Shells
3 orbiting shells of electrons around the nucleus.
1st shell has 2 electrons
2nd shell has 8
3rd has 8
What do atoms want?
2 things:
1. The outer shell to be full
2. A neutral charge (# of protons = # of electrons)
What are right column atoms?
Noble gasses
Generally don’t interact with other elements & have a full outer shell (same # of protons and electrons)
What are ions?
Atoms on a small molecule with an electrical charge.
The # of protons + electrons are different but make a full outer shell.
Anions
Ions with a negative cahrge.
protons < electrons
Cations
Ions with a positive charge
protons > electrons
Ionic bond
When possitive and negative ions attract and form a bond.
(-)Anion + (+)Cation –> negative attracts positive
ex: table salt - NaCl
List of important ions
Name + Periodic lable
- Sodium - Na+
- Chloride - Cl-
- Potassium- K+
- Calcium - Ca++
- Magnesium - Mg ++
- Iron - Fe (2+ or 3+)
What is a covalant bond?
2 atoms held together by sharing electrons.
This allows atoms to have a full outer shell with a neutral charge, forming a bond stronger than ionic bonds.
Single bond
2 atoms sharing 2 electrons
ex: H-H / H-O-H
Double bond
2 atoms sharing 4 electrons
ex: O=O (molecular oxygen)
What are molecules?
2 or more atoms held together by a covalant bond
Molecular formula
Refers to how many atoms in each element are found in molecules. It’s expressed at the bottom right
Polar Covalent Bonds
Covalent bond where 2 atoms don’t share electrons equally
* Atom pulls more has slight negative (-) charge
* Atom that less has slight positive charge
Chemical Reactions
Occur when molecules change into different molecules.
The arrangement of atoms into molecules changes but the number of atoms of each element doesn’t change.
