Atoms
What is an atom?
the smallest piece of an element
What are molecules?
the simplest unit of a chemical substance, usually a group of two or more atoms
What is involved in chemistry?
the study of matter--what it is made of, what its usual characteristics are and how it reacts to other matter
Acids are sour.
Which ionic compound is produced from a reaction between an acid and a base?
salt
What is an element?
a substance; only one kind of atom
What do chemical formulas have?
chemical symbols and numbers to abbreviate the name of a compound
What do you call an atom that has gained or lost electrons (the number of electrons do NOT equal the number of protons)?
ion
How do bases taste and feel?
Bases are bitter and slippery.
Which scientist developed a simplified model of an atom?
Niels Bohr
Which two parts make up the nucleus? What can you calculate when you add these two up?
protons and neutrons; atomic mass
What are compounds?
Compounds are a kind of molecule produced as a result of a chemical change or reaction. They are molecules that combine two or more different elements.
What do you call when atoms share pairs of electrons? What happens due to their sharing of electrons?
covalent bonds; the electrons fill in more of the outer shells of both atoms
What are corrosive acids? What can they do?
They are highly acidic and dangerous acids that burn your skin. They can even dissolve metals.
Which scientist came up with a way to organize and classify all of the elements (Periodic Table of the Elements)?
Dmitri Mendeleev
Which part of the atom travels around the nucleus? What is its charge? How much does it weigh?
electrons; negatively charged; so light that they contribute almost nothing to the mass of an atom
What happens when different types of atoms join together?
a chemical change or reaction
How do ionic bonds form?
when positively and negatively charged ions attract each other
What are some examples of acids? What are some examples of bases?
hydrochloric acid, gastric juices, lemon, vinegar, tomato juice, coffee, milk
baking soda, soap, bleach, toothpaste, antacid
What do periods show in a periodic table? What do groups show?
Periods show how many shells of electrons the element has.
Groups show how many electrons are in the element's outer shell; elements in the same group have similar physical and chemical properties.
Atoms share electrons in ______________________.
a covalent bond
How are molecules produced?
Some are produced when atoms of the same element combine.
Others are produced when atoms of two or more different elements combine through a chemical change or reaction.
Explain what happens during synthesis reaction and decomposition reaction.
synthesis: when molecules combine to form new substances
decomposition: when a compound is broken down into simpler compounds
What do the two compounds (acids and bases) form when dissolved in water?
H+ (hydrogen ions) - acids
OH- (hydroxide ions) - bases
Which scale do we use to determine the concentration of an acid or a base in a solution? Explain the range for acids and the range for bases.
the pH scale numbered from 0-14; acids measure from 0 to 6.9; bases measure from 7.1-14; solutions with a pH of 7.0 is neutral like pure water