Density is the amount of matter there is in a certain amount of space. Density = Mass / Volume Unit is g / cm 3 Frank has a paper clip. It has.

Review Session #1

Density is the amount of matter there is in a certain amount of space.

Density = Mass / Volume Unit is g / cm3

Frank has a paper clip. It has a mass of 9g and a volume of 3cm3. What is its density?

Density

Atoms are composed of Protons, Neutrons, and Electrons.

Protons and neutrons are found in the nucleus and electrons are in shells outside the nucleus.

The Atomic number is the number of protons and electrons in a neutral atom.

The number of neutrons can be found by subtracting the number of protons from the atomic mass.

Each element has a specific number of protons and that number cannot be changed.

Atoms

Isotopes are atoms of the same element that have a different number of neutrons.

There are two different ways to indicate an isotope. ◦ Boron-10 Boron-11◦ Or 17

35 Cl the top number is the mass number and the bottom number is the atomic number.

Atoms cont.

The periodic table is an organization of all of the elements by properties and by atomic number.

Columns are called “Groups” and the group also tells us how many valence electrons an atom of an element contains. Elements in each group have similar chemical properties.

Rows are called “Periods” and the period tells us how many electron shells an atom of an element contains.

The Periodic Table

The periodic table is divided into 3 regions:◦ Metals, Nonmetals & Metalliods◦ What are some properties of each?

Make sure to study your notes on page 20 for each of the families on the Periodic Table.

Structures of the atoms:◦ Bohr Diagrams:

First shell = 2 electrons Second shell = 8 electrons Third shell = 18 electrons Fourth shell = 32 electrons

Practice drawing Al

Periodic Table cont.

◦ Electron Dot Diagrams: List only the chemical symbol and ONLY the valence

electrons that the element contains. Practice drawing Cl

Periodic Table cont.

When atoms bond they can gain, lose, or share electrons◦ An ion is an atom that has gamed or lost an

electron making it have a net charge◦ A Cation is an ion with a positive charge. The

atom has lost electrons.◦ An Anion is an ion with a negative charge. The

atom has gained electrons. Each group on the Periodic Table will

gain/lose electrons and will have a different charge called the Oxidation Number.

Bonding

Octet Rule: Every atom wants 8 outer valence electrons in order to become stable. They can achieve this by gaining, losing, or sharing electrons.

This gaining, losing, and sharing is called chemical bonding.◦ Ionic Boding

Losing of electrons Forms between metals and non-metals Forms crystalline solids with high melting points

Bonding cont.

◦ Covalent Bonding Sharing of electrons Forms between two non-metals.

Study your notes for naming bonds

Bonding cont.

Law of Conservation of Matter – states that in a chemical reaction matter can be neither created or destroyed.

The mass you have before the reaction has to equal the mass after the reaction.

There are several signs of a chemical reaction◦ Light given off, the formation of a precipitate,

production of a gas, heat given off and color change.

Practice Balancing Chemical Equations◦ Remember that you cannot change the subscript only

the coefficient.

Balancing Chemical Equations

Direct Combination or Synthesis Reaction◦ A + B = AB

Chemical Decomposition or Analysis reaction◦ AB A + B

Single Displacement◦ A + BC AC + B

Double Displacement◦ AB + CD AD + CB

Practice Classifying Chemical Equations

Classifying Chemical Equations

Atoms decay when the strong force is not large enough to hold a nucleus together. Energy and particles are given off. The larger the elements are unstable and tend to decay. Nuclei with too few or too many neutrons compared to the protons are radioactive and will decay.

Radioactivity

There are 3 particles that can be given off during decay

Radioactivity cont.

Alpha Decay

Beta Decay

Gamma Radiation

What is released?

2 protons and 2 neutrons (Helium gas)

Electron from nucleus (proton changes)

Gamma Rays

Particles or EM waves

Particle Particle EM Wave

Interesting facts

Not harmful unless inside the body

Can penetrate some skin

Destroys DNA

The amount of time it takes for half the nuclei in a sample to decay is called the half-life.

Half-life can vary greatly from a few seconds to thousands or millions of years.

Problem:◦ If a human body contained 50g of C-14 and now

had only 25g, how old is the body?◦ C-14 is 12.5g?

◦ Hint: half-life of Carbon-14 is 5,730 years.

Radioactive Half-Life

When atoms combine the form molecules (two or more of the same element) or compounds (two or more different elements).

Molecules of elements and molecules of compounds are both pure substances (must be separated by chemical means).

Mixtures are not pure substances (can be separated by physical means). Can be Homogeneous or Heterogeneous.

Matter

Solid, Liquid, Gas – Remember how the particles are moving in each

What happens as you add heat to each state of matter?

Kinetic Theory◦ All matter is composed of small particles (atoms)◦ Particles are in constant motion◦ Particles are colliding with each other and with

the walls of their container.

3 States of Matter

According to Boyle’s Law – as pressure increases, volume decreases.◦ P1V1 = P2V2

According to Charles Law – as temperature increases, volume increases.◦ V1 \ T1 = V2 \ T2

Boyle’s Law & Charles’ Law

Solute – the substance being dissolved.◦ Example: Salt

Solvent – the substance doing the dissolving.◦ Example: Water

A concentrated solution is a solution that has a large amount of solute.

A dilute solution is a solution that has a small amount of solute.

Solubility is the maximum amount of solute that can be dissolved in a given amount of solvent at a given temperature.

Solutions

Saturated – contains all the solute that a solvent can hold at a given temperature.

Unsaturated – a solution that can dissolve more solute at a given temperature.

Supersaturated – a solution that contains more solute than can be dissolved at a given temperature.

Solubility Curves

Types of Solutions

Stirring – brings more fresh solvent into contact with more solute.

Crystal size – increases the surface area by creating smaller particles.

Temperature – causes the solvent to bump into the solute and dissolve faster.

How to increase the rate of dissolving?

http://www.thesciencequeen.net/acidnotes.pdf

Acids and Bases