Science - Chapter 6
the difference between an element and a compound
An element is made of only one type of atom; a compound is made of more than one type of atom.
the formula for carbon dioxide
CO2
symbol for chlorine
Cl
symbol for hydrogen
H
the formula for water
H2O
What is the difference between a mixture and a compound?
In order for a blend of two different substances to be called a compound, the different types of atoms have to be bonded together.
Why is sodium chloride not considered a molecular compound?
It is not made of individual molecules, but consists of geometric crystals, containing equal numbers of sodium and chlorine atoms.
What is the difference between mass and weight?
Mass is the amount of matter that makes up an object; weight is a measure of the pull of gravity on an object.
Can two atoms of the same element ever have different atomic numbers?
No; each element has its own atomic number because each element is composed of a unique type of atom.
symbol for oxygen
O
Which would weigh more, a brick made of iron or the same size brick made of lead?
a brick of lead
the metals in the first (far left) column of the periodic table
alkali metals
the second column of elements in the periodic table
alkaline earth metals
Which is more dense, oak wood or aluminum?
aluminum
a noble gas commonly used as filler in incandescent light bulbs; the most plentiful of the noble gases
argon
each element has it own number because each element is composed of a unique type of atom
atomic number
name for the number of protons in an atom
atomic number
the tiny particles that matter is composed of
atoms
a halogen that is liquid at room temperature ; used in photographic film
bromine
the most common alkaline earth metal; an ingredient in calcium carbonate
calcium
the element that comes in the forms of graphite and diamond
carbon
a process in which atoms of elements or compounds are rearranged to form new substances
chemical reaction
the study of what substances are made of, and how one substance can be changed into another
chemistry
the most widely used halogen; used in bleach, disinfectants, and PVC; an ingredient in table salt
chlorine
"chrome"; a shiny metal often applied to polished steel to prevent it from rusting
chromium
the type of a chemical reaction that occurs whenever a substance reacts rapidly with oxygen
combustion (or burning)
a substance composed of more than one type of atom bonded together
compound
substances that are composed of more than one type of atom bonded together
compounds
a geometric arrangement of atoms
crystal
the amount of matter (mass) in one unit of volume
density
the hardest of all known substances
diamond
the cloudlike shield around an atom's nucleus formed by the atom's fast-moving electrons; prevents other atoms from moving into the same space
electron cloud
the tiny particles that swarm at tremendous speed around the nucleus of an atom
electrons
substances that are composed of only one type of atom
elements
a halogen used in toothpaste, coolants, Teflon, and high-powered military lasers
fluorine
the units in which mass is measured
grams or kilograms
the elements in the next to last column of the periodic table, highly reactive, showing a tendency to form compounds with alkali and alkaline earth metals
halogens
a noble gas used in balloons and lasers
helium
a colorless and odorless gas used in chemical factories and as a rocket fuel
hydrogen
the element with the lowest atomic number
hydrogen
the most abundant element in the universe as a whole
hydrogen
the simplest kind of atom, with only a single electron whirling around a single proton
hydrogen
a solid halogen that sublimes when heated (it turns directly into gas); used in iodized salt and medical antiseptics
iodine
What type of compound is sodium chloride?
ionic compound
a compound composed of charged atoms or groups of atoms
ionic compound
the densest of everyday metals; used to make car and truck batteries, wheel weights, and firearms ammunition
lead
a strong but lightweight alkali metal used in parts for airplanes and some cars
magnesium
the amount of matter that makes up an object
mass
anything that takes up space and has mass
matter
the only metal that is liquid at room temperature
mercury
the elements toward the left side of the periodic table that tend to have a lustrous silvery color and are good conductors of electricity and heat
metals
three main groups of elements
metals, nonmetals, semimetals
a compound composed of individual molecules
molecular compounds
a tiny group of two or more atoms that are bonded tightly together
molecule
a noble gas used in signs and lasers
neon
anything lacking an electrical charge
neutral
a very hard metal that is used to make stainless steel, rechargeable batteries, tanks to hold corrosive chemicals, and the five-cent coin
nickel
the most abundant nonmetal gases in the atmosphere
nitrogen (78%) oxygen (21%)
the elements in the last column of the periodic table; are gases and do not combine with other elements except under very unusual circumstances
noble gases
the elements located at the right side of the periodic table; include many solids and several gases
nonmetals
substances made of geometric structures containing may trillions of atoms all bonded together
nonmolecular compounds
the tiny, extremely dense core at the center of an atom
nucleus
the densest element of all
osmium
the most abundant element in the earth's crust
oxygen
the most abundant element in your body
oxygen
a chart constructed by Dmitri Mendeleev to arrange the elements in such a way as to group similar elements together
periodic table of the elements
a waxlike solid with two forms, white and red
phosphorus
the transuranium element that is the most abundant
plutonium
a common alkali metal found in the rocks, soils, and oceans of the earth; does not occur naturally in pure form
potassium
the two types of particles which make up the nucleus of an atom
protons (positive charge) neutrons (negative charge)
a group of electrons in an atom that orbit at roughly the same distance from the nucleus
shell
a semimetal that is an ingredient in sand, quartz, and glass; in pure form, used to make computer chips
silicon
a common alkali metal that is an ingredient in table salt and lye; also used in street lights
sodium
to turn directly from a solid into a gas (such as iodine does when heated)
sublime
an odorless, yellow solid called brimstone in the Bible; flammable and burns easily
sulfur
a highly corrosive chemical used in car batteries and chemical manufacturing
sulfuric acid
a measure of the pull of gravity on an object
weight
a metal often used to coat steel to prevent it from rusting; also used in flashlight batteries
zinc
