what is an atom
the smallest unit of matter
what is an element
consists of 1 type of atom
what is a compound
2 or more atoms that are chemically bonded
what is a mixture
consists of 2 or more atoms that aren’t bonded
what is the atomic number
number of protons (number of elements)
top number
what is the mass number
bottom number (protons + neutrons)
Outline the subatomic particles: protons, neutrons, and electrons in terms of charge and mass.
Protons
Positive (+) charge
Mass of 1 (heavy)
Found in the nucleus
Neutrons
No charge (neutral)
Mass of 1 (heavy)
Found in the nucleus
Electrons
Negative (–) charge
Very small mass (almost 0)
Move around the nucleus in shells
Summary:
Protons and neutrons are in the nucleus and make up most of the atom’s mass.
Electrons move around the nucleus and control how the atom reacts.
what is the def of a mixture
A mixture is made of two or more substances that are not chemically joined
what is the def of a pure substance
a pure substance contains only one type of particle.
Distinguish between an element, compound, and mixture.
An element is made of only one type of atom.
A compound is made of two or more elements chemically joined together.
A mixture is made of two or more substances that are not chemically joined.
Distinguish between a molecule and a lattice (which refer to the
arrangement of particles in a substance)
A molecule is a group of atoms bonded together. A lattice is the pattern in which particles are arranged in a solid.
water and glucose are ________ compunds
molecule
sodium chloride (table salt) and silicon dioxide (in sand) are
________ compounds
lattice
__________ compounds have lower melting and boiling points than ________ compounds, which have stronger bonds.
molecular
lattice
Subscript numbers show how many atoms of an element are in a ________
molecule
Subscript ratios show how many atoms of each element are in the ______
lattice
Describe the common properties of metals:
Relate the properties of copper to its uses.
Relate the properties of iron to its uses
Properties of metals include being lustrous, malleable, ductile, and good conductors.
Copper is used in wires and pipes because it conducts electricity well and resists corrosion.
Iron is used in buildings and tools because it is strong and magnetic.
Describe the common properties of non-metals:
Relate the properties of carbon diamond to its uses.
Relate the properties of carbon graphite to its uses
Non-metals are poor conductors, brittle, and have low melting points.
Diamond is very hard and used in cutting tools and jewellery.
Graphite is soft, conducts electricity, and is used in pencils and batteries.
Define a chemical change as:
a change in which a new
substance is formed.
Compare physical and chemical changes in terms of the arrangement of particles and reversibility of the process
Physical changes change particle arrangement but keep the same substance; they are reversible.
Chemical changes form new substances; they are usually irreversible.
Define a physical change as:
a change in appearance without a new substance forming
Describe what occurs to atoms in a substance during a physical change compared to a chemical change.
In a physical change, atoms rearrange but stay the same substance.
In a chemical change, atoms react to form new substances with different properties.
A chemical change occurs when ___________ changes, _________ appear, or _______ substances disappear.
temperature
new substances
original
List signs of a chemical change/reaction
Signs of a chemical change include color change, gas formation, precipitate, temperature change, or light production.
