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