Catégories : Tous - mass - elements - compounds - matter

par Kal Bri Il y a 4 années

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Chemistry Definitions

The text provides an overview of basic chemistry concepts, focusing on the composition and classification of matter. It explains how to determine the number of neutrons in an atom by subtracting the atomic number from the mass number.

Chemistry Definitions

Chemistry Definitions

Classification of Matter

A flowchart with examples
What the particles would look like
Mixtures
Can be separated by physical means
Made up of more than one kind of molecule
Heterogenous Mixture (mechanical mixture): A mixture where more than one substance is visible. ex. compost
Homogeneous Mixture (Solution): Particles mix well with each other, so well that you can only see one phase or visible part. ex. salt mixed into water
Compound: Pure substances that contain two or more different elements formed for a chemical reaction
Can be broken down by chemical means
Made up of more than one kind of atom
Element: Pure substances that can be broken down into simpler substances
Cannot be broken down by chemical means
Made up of only one type of atom
Pure substances: A substance that contains only one type of particle
Matter: Anything that has a mass and takes up space (it has a volume)
Molecules: Pure substances where the atoms combining can be the same or different. ex. O2, H2O

Bohr-Rutherford Diagram

An example of what the Bohr-Rutherford Diagram looks like
On the energy levels, there are the electrons that orbit around the nucleus. 2 on the innermost shell (level) and 8 on all the others
Each row (called periods on the periodic table) have the same number of energy levels as the number of row they're in
Example: Period 1 (hydrogen and helium) have one energy level where the electrons orbit around the nucleus
Energy levels are called shells

Picture of definitions on the periodic table

Atomic Number

The number of protons in the nucleus (same number of electrons)
Smaller of the two numbers

Element Symbol

The symbol used to identify an element (eg. Co for Cobalt)

Mass Number

The mass of an atom of that element
The bigger of the two numbers. Used to find number of neutrons
How To Get Mass Number
Mass number = atomic number + number of neutrons

How To Find Number Of Protons, Neutrons, and Electrons

Number of Electrons: same as number of protons
Number Of Neutrons: Atomic Mass subtracted by Atomic Number
Number of Protons: Atomic number

Hydrogen

Grouped with alkali metals but does not have the same properties
Behaves like a non metal

Metalloids

Elements that posses both metal and nonmetal properties
Found on the "staircase"

Halogens

Examples: Fluorine, Bromine, Chlorine
Like to form salts
Have 7 electrons in their outer orbit
Most reactive nonmetals
Occupy the 17th column

Alkaline Earth Metals

Examples: Magnesium, Calcium Barium
React with acids
Have two electrons in their outer orbit
Reactive but not as reactive as alkali metals
Occupy the 2nd column

Alkali Metals

Examples: Lithium, Potassium, Sodium
Release hydrogen when mixed with water
Have 1 electron in their outer orbit
Are extremely reactive
Occupy the 1st column

Noble Gases

Examples: Neon, Argon, Helium
Don't form compounds
Have a stable electron configuration (8 electrons)
All are unreactive
All gases are room temperature
Found at the far right of the table

Electrons

Orbits around nucleus
Almost 0 amu (atomic mass unit)
Negative charge

Protons

Positive charge

Neutrons

How To Get Number Of Neutrons
neutron number = mass - atomic number
found in nucleus
1 amu (atomic mass unit)
Neutral charge