Atoms!Ya can’t trust them, they make up everything!

Matter• Matter is anything that has mass and takes up space!• We have many different types of matter: pure substances, and mixtures.

• Law of Conservation of Matter – Matter can be neither created nor destroyed, merely transformed.

Most basic chemical - Atoms• Atoms are the smallest particles to have chemical properties.

• There are smaller particles, but they do not have chemical properties

• Atoms are made up of smaller particles called protons, neutrons, and electrons

• Different numbers of protons, neutrons and electrons determine an atom’s properties

Subatomic Particles

• Protons, Neutrons, and Electrons are called subatomic particles

because they are what make up atoms.

“Sub” meaning “within” or “beneath” the atom

Subatomic particles• Protons are:

• POSITIVELY CHARGED like the south end of a magnet

• BIG and GIVE the atom MASS

• They do not move within the atom

• They give the element its identity

• Neutrons are:

• NEUTRAL/HAVE NO CHARGE

• BIG and GIVE the atom MASS

• They do not move within the atom

• Stabilize the protons

Make up an atom’s nucleus

Subatomic particles (continued)• Electrons are:

• NEGATIVELY CHARGED like the north end of the magnet

• SMALL and DO NOT give the atom MASS

• Move rapidly around the nucleus

• Their movement is responsible for chemical reactions

Make up an atom’s electron cloud

Each atom has a nucleus made up of protons and neutrons

Each element has a unique number of protons

Properties of an atom

• Atomic number: the number of protons; it tells us which element the atom is for.

• Mass number: the number of protons plus the number of neutrons; how much the atom weighs.

• Charge: the positive charges plus the negative charges; if it is neutral, the number of protons is equal to the number of electrons

Atoms and Subatomic Particles• If an atom is neutral, the # of electrons equals the atomic number

• IF NEUTRAL: # electrons = # protons • If you are given an atom’s atomic mass #, you can calculate the

number of neutrons by subtracting the number of protons from this atomic mass #

• Mass # - Atomic # = # of Neutrons• If you have the # of neutrons you can add them to the # of protons

to discover the mass number• Atomic # + # of Neutrons = Mass #

Pure substances - Atoms• Pure substances contain only one type of particle (a unit of chemistry),

whether they are atoms or compounds

There are different types of atoms called elements.

• Each element has a different number of protons

• Each element has different characteristics from one another, especially associated with their class

Ions/ Isotopes

•Ions – atoms that have charge due to losing/gaining electron(s).

•Example: Na – electron = Na +1•Example: F + electron = Na -1

*Isotopes – atoms of the same element that have a different # of neutrons & mass.

12C6 = 6 protons & 6 neutrons vs. 13C6 = 6 protons & 7 neutrons

Periodic table

• Our periodic table directly tells us:

• The atomic number (how many protons)

• The average atomic mass (an average of all the atoms of that element)

• The symbol of the element

• The name of the element

Periodic Table

• Our periodic table tells us whether an element is a :

• a metal (to the left of the staircase)

• metalloid (touching the stair case)

• non-metal (to the right of the stair case)

• noble gas (the last column on the right)

**(These are classes of elements)

Metals

Metalloids

Non-metals

Noble gases

Pure Substances - Compounds

• When elements chemically bond together, they form a NEW UNIT of matter called a compound

• Compounds have different properties from the elements that make them up• Example, both hydrogen and oxygen support flame, yet, H2O (Water) puts out

flames!

Mixtures – a substance that contains 2 or more units of chemistry• Homogeneous –mixtures that are evenly distributed, even on the

atomic/molecular level

• Heterogeneous – mixtures that are not evenly distributed 100%, especially not on the atomic/molecular level.