Midterm Flashcards
The three types of radiation and their penetration abilities:
Properties of Ionic Compounds
Crystalline Structure High Melting Point Rigid Strong Bond Conduct Electricity (when dissolved or melted) Good Insulators
Conductor
A material which permits the flow of energy. A material which allows the flow of charged particles is an electrical conductor. A material which allows the transfer of thermal energy is a thermal conductor or heat conductor.
Photon
Energy given off in the form of light by an excited electron. Otherwise known as a “quanta of light”.
Charge of Group 2 or 2A (Be, Mg, Ca, Sr, Ba):
Charge = 2+
Sublevel
Principal energy levels are broken down into sublevels designated s, p, d, or f upon which electrons travel.
Proton
Positively charged subatomic particle. Contained inside the nucleus. Neutrons and Protons weigh roughly the same (1 atomic mass unit).
Cations
Positively Charged Ions. In general, cations are metals.
Hund’s Rule
When filling sublevels other than s, electrons are placed in individual orbitals before they are paired up.
Electrons fill like people do on a bus. You would never sit right next to someone you do not know if there are free seats available, unless of course all the seats are taken then you must pair up.
So, when working with the p sublevel, electrons fill like this…up, up, up….down, down, down…
Ionic Compound Formulas
- Metal written first Nonmetal written second 2. Use criss-cross method and subscripts to insure sum of charges = 0
Predict the element formed and write a balanced nuclear equation for the following statement:
Uranium-238 decays by alpha emission to form __________.
Anion
Negatively charged Ions. Anions are negatively charged because they have gained an electron(s) (electrons are negative). In general, anions are nonmetals.
Intramolecular Forces
Attractive forces WITHIN a molecule (Ionic & Covalent Bonds)
Fission
Radioactivity
When the nucleus of an atom becomes unstable and decays. This tends to happen to large atoms (larger than atomic number 83) becuase the number of protons to neutrons in the nucleus is unbalanced.
Naming Covalent Compunds
You DO NOT use the “criss-cross” method. Use prefixes. The only time you do not use a prefix is when there is only one of the first nonmetal. Remember : 1-Mono 2-Di etc…
Rules for Writing Lewis Dot Structures
- Total the Valence Electrons and Update during each step.
- Form a single bond between the central atom and each surrounding atom (each bond uses two electrons).
- Place electrons around the outer atoms until you run out or they each have eight electrons around them. (Hydrogen and Helium can only have two electrons around them).
- Place any remaining electrons around the central atom.
- Does each atom other than hydrogen have eight electrons around it?
- Rearrange (share) electrons so that all atoms other than hydrogen have eight electrons around them.
Orbital
Sublevels can be broken down into regions called “orbitals”. An orbital is defined as the most probable location for finding an electron. Each orbital holds 2 electrons.
Greek Prefixes used in nomenclature 1= 2 = 3 = 4= 5 = 6= 7= 8= 9= 10=
1= mono 2 =di 3 =tri 4=tetra 5 = penta 6=hexa 7=hepta 8=octa 9=nona 10=deca
Pauli Exclusion Principle
If there are two electrons in an orbital, they must have opposite (paired) spins.
Atomic Size
Size of an atom.
Depends on the number of energy levels and the overall charge of the nucleus (the nucleus’s charge depends on the number of protons).
As you go down a group you are adding energy levels (rings around the nucleus) so the atomic size increases.
As you go across a period the atomic size decreases because the energy levels (which contain negative electrons) are increasingly attracted to the positive protons in the nucleus of the atom.
Period
Horizontal row on the periodic table.
How to calculate neutrons:
of Neutrons = Atomic Mass Number - Atomic Number
Hydrogen
Group 1 Nonmetal
Polar Covalent
A type of covalent bond between two atoms in which electrons are shared unequally. Because of this, one end of the molecule has a slightly negative charge and the other a slightly positive charge.
Fusion
Metals
To the left side of the periodic table (left of the zig zag line).
Usually, solids at room temperature.
Good conductors of heat and electricity.
High melting and boiling points.
Malleable.
Ductile.
Transition Metals
Malleable
Able to be hammered or pressed permenately out of it’s original shape without breaking or cracking.
Covalent or Molecular Compounds (Molecules)
The first word gives name of the element that appears first preceded by a prefix that shows number of atoms in that element. Do NOT use the prefix mono before the name of the first element. The second word consists of a prefix designating the number of atoms of that element, the stem name of the second element, and the suffix -ide.