Atoms, Molecules, Elements & Chemicals Flashcards
(98 cards)
What is the atomic number?
number of protons in atoms
also number of electrons in neutral charged atoms
What are isotopes?
atoms with unequal protons and neutrons
What is the mass number of an atom?
How massive the atom is/number of protons plus number of neutrons (Electrons are so small, they don’t count in the atomic mass)
What are periods, groups, and families.
Periods are rows in the periodic table
Groups and families are interchangeable terms referring to the columns in the periodic table.
What is significant about the group number an atom is found in on the periodic table?
Group number is the number of valence electrons (electrons in outer shell) that a neutral atom of that element has.
True or false: Electrons move in a circular orbit around the nucleus of an atom
False: Electrons move in more of a wave pattern than a circular pattern
Who is Robert Milikan?
discovered the fundamental charge of an atom
What important factor has everything to do with how atoms react with each other?
the number of valence electrons
Define chemical reaction
the formation or breaking of chemical bonds to form new molecules.
Define photosynthesis and combustion
Photosynthesis = absorbtion of energy Combustion = release of energy
True or false: Chemical bonds are electrical
True: Chemical bonds are electrical because they are formed by electrical attraction
What is the octet rule?
Atoms always attempt to have full outer shells of 8 valence electrons. This can happen through sharing or through taking
What are the three types of bonds that happen between atoms?
3 types of bonds
- Ionic: One atom gives and one takes
- Covalent: Electrons are shared between atoms
- Metallic (not important to know for this class)
What is electronegativity?
Electronegativity is a measure of how much atoms want electrons. The more they already have, the more they want to get up to 8. The less they have, the more likely they are to give up what they already have.
You can remember this by remembering the words of Jesus in Matthew 13:12 - “For to the one who has, more will be given, and he will have an abundance, but from the one who has not, even what he has will be taken away”
When naming chemical compounds, what does an ending of “ide” mean?
An ending of “ide” means the compound contains only two elements
What is the difference between an empirical and a molecular formula?
Empirical formula: written down in lowest ratio
Molecular formula: identifies actual number of molecules
True or false: Covalent bonds are always written as empirical formulas
False: Ionic bonds are always written as empirical formulas
OR
Empirical formulas can be the lowest ratio of a covalent compound
What is formula weight?
Formula weight is the sum of atomic weights of all atoms in a formula
What is percent composition?
Percent composition is what percentage by atomic weight each element takes up in a compound
What is a mole?
Mole is a scientific number used for counting very small objects such as how many water molecules in a glass of water.
One mole = 6.02 x 10^23 (or 602,000,000,000,000,000,000,000
Know how to balance equations
Balancing equations is like a fun mind puzzle. Essentially, you need to make both sides of the equation equal by adding coefficients before the molecules in an equation. Sometimes, this is best done by trial and error.
I recommend trying to get some practice on this before exam time.
What is special about hydro-carbon and oxygen?
Whenever you have hydro-carbon in any amount in the presence of oxygen, you will always see a result of Carbon Dioxide & Water. This is one of very few reactions we can guarantee the results of every time.
True or false: When writing names of ionic compounds, always write the nonmetal first.
FALSE: When writing names of ionic compounds, always write the metal first.
True or False: Elements in the same row of the periodic table exhibit similar chemical properties.
FALSE: Elements in the same column (or group) of the periodic table exhibit similar chemical properties.
