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Matter and its Changes. Atoms . Matter is made up of atoms Matter is anything that takes up space and has mass Atoms are the “building blocks” of life. Forms of matter that contain only one type of atom are called elements Atoms combine to form many different types of matter.
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Atoms • Matter is made up of atoms • Matter is anything that takes up space and has mass • Atoms are the “building blocks” of life
Forms of matter that contain only one type of atom are called elements • Atoms combine to form many different types of matter
Structure of an Atom Electron (electron cloud) Proton Mass Number = Protons + Neutrons Atomic Number = Number of protons Neutron
Isotopes • When the number of protons in an atom changes it becomes a different element • Atom is electrically neutral when there are more neutrons than protons • Atoms of the same element that have a different number of neutrons are called isotopes • Ex. C12 = 6p +6n C14 = 6p + 8n
Ions • Electrically charged atoms are called Ions • The number of protons is not equal to the number of electrons • Ions are attracted to each other when they have opposite charges • Ex. Na+ + Cl- = NaCl = salt • Ex. Na+ + F- = Sodium Fluoride for toothpaste
Atoms combine by sharing their outermost electrons in their electron clouds • When two atoms are combined a molecule is formed
Bonds • Ionic Bond – Positive and Negative ions combine and electrons are transferred • Ex. NaCl • Covalent Bond – Electrons are shared • Ex. H2O
How Atoms Combine • When at least two atoms are combined a molecule is formed • There are two ways in which atoms combine to form molecules and compounds
Ionic Bonding • Positive and Negative ions combine and electrons are transferred • Example: Na+ and Cl- = NaCl
Covalent Bonding • In covalent bonding electrons are shared • Example: 2H + O = H2O
Compound A type of matter that has properties different from the properties of each of the elements in it • Example: Na (metal) + Cl (gas) = NaCl (solid salt) • Example: 2H (gas) + O (gas) = H2O (liquid water)
Mixture • Many different substances that when mixed together, each substance retains its own properties • Examples: sand, air and salad
Solution • When one substance of a mixture is dissolved in another substance it is a solution • Examples: tea w/ sugar, salt water
Chemical/Physical Properties • Chemical properties describe how one substance changes when it reacts with another • Examples: iron and oxygen = rust • Physical Properties can be observed or measured without changing the substance • Examples: color, shape, size, density and texture
What is density? • The measure of the mass of an object divided by its volume.
4. Liquid to a solid: freezing point 5. Solid to a liquid: boiling point 6. Only substance that occurs naturally as a solid, liquid, and gas: Water
Matter can change by: • Increasing or decreasing the temperature Ex: freezing water turns it to a solid (ice) 2. Increasing or decreasing pressure Ex: Pressure to ice cube changes it to liquid
Energy from Atoms • What is nuclear energy? • Alternate energy source produced from atomic reactions 2. How fission produces nuclear energy: - Splitting the nucleus of atoms in heavy elements
3. Most commonly used fuel in nuclear power plants: - Uranium 235 Where is it found? - Sandstones in the Rocky Mountains
4. Major source of nuclear waste: - Radioactive material Most common method of storing nuclear waste: • Power plants Can remain active for 10,000 years
Two advantages to storing nuclear waste at Yucca Mountain: • Remote area (deserted) • Water table is far below storage facility
Two disadvantages to storing nuclear waste at Yucca Mountain: • Earthquakes could destroy storage facility • Large amount of nuclear waste in one area