Chemistry Finals Study Guide

Mass = # of protons + # of neutrons

Average atomic mass = (% abundance atomic mass of isotope) + (% abundance atomic mass of isotope)

Density= mass/volume (heart)

Percent error = |Measure value-accepted value/ accepted value| * 100

Energy = planks constant *  wavelength 

Energy = Planks constant * speed of light / wavelength 

Frequency = speed of light / wavelength 

m2=m1(1/2)^(t2/t1)

m2=mass remaining

m1=original mass

t2=time

t1= half-life

1. What is/are the unit of measurement for: 

   1. Mass: Grams (g),

   2. Volume: cm^3, liters (L)

   3. Length: meters (m)

   4. Atom: amu

   5. Density: g/cm^3, g/mL

JJ. Thomson: studied the flow of electric currents, discovered electrons, proposed that electrons were embedded within the atom. (w/out any organization)

"plum pudding model"

E. Rutherford: through his gold foil experiment, he proposed that protons are concentrated in a center called the nucleus. Electrons revolve in orbitals around nucleus

Bohr: the energy of each electron in an atom must be quantized. Each energy level (orbital) is given a quantum number, n. The lowest energy level (closest to nucleus) is called ground state, n=1. when an electron absorbs energy, it jumps to a higher energy level called excited state. When energy is released or emitted, the electron falls back to a lower energy level

Mendeleev: developed the early periodic table. organized elements by increasing atomic mass Arranged in a way so that the elements in the same column have similar properties

1. State all the postulates to Dalton’s atomic theory 

   1. Atoms can neither be divided nor destroyed.

   2. All atoms of an element are identical.

   3. Atoms of different elements differ.

   4. Atoms of different elements combine in whole ratios to form compounds.

   5. Chemical reactions consist of combination, rearrangement & separation of atoms.

   Define physical and chemical changes and give 3 examples of each

   1. Physical: Changes into the same kind of matter (melting, cutting, bending)

   2. Chemical: Matter changes into a different kind of matter (chemical bonds are broken and cannot be restored), substance cannot be restored (burning, cooking, rust)

   What are the 4 types of radioactive particles? Describe the properties of each. 

   1. Alpha (α)

      1. High energy particles, represented as ​, does not have much penetrating power 

   2. Beta (β)

      1. High speed electrons, represented as , 100 times more penetrating than alpha particles 

   3. Gamma  (γ)

      1. Very energetic form of light, represented as , most penetrating and harmful

   4. Neutrons 

      1. , high penetrating (can pass through many materials), speed varies, can make objects radioactive, more penetrating than gamma radiation 

Describe the Heisenberg uncertainty principle

1. The position of a moving object cannot simultaneously be measured and known exactly 

What does the Pauli exclusion principle state about the spins of electrons?

1. A suborbital can only hold a maximum of 2 electrons and must have opposite spins ⇅

Early periodic table: elements organized by increasing atomic mass, arranged in a way so elements in the same column have similar properties

Todays periodic table: arranged according to periodic law, elements have a common number of valence electrons

1. Metals (located on the left of the staircase)

   1. Good conductors of electricity 

   2. Solid at room temp (except mercury)

   3. Malleable (sheets) 

   4. Ductile (fine wires)

   5. Cations (+ charge)

2. Nonmetals (located on the rights side of the stair case)

   1. Poor conductors of electricity 

   2. Gas, liquid, or solid at room temp

   3. Anions (- charge)

3. Transition metals (located in the d-orbital, some in p, rectangle)

   1. Not as reactive as other metals 

   2. Typically metallic properties 

   3. Good conductors 

   4. High luster 

4. Metalloids (located on the staircase)

   1. Semiconductors 

   2. Brittle solid at room temperature 

5. Inner transition metals (located on f-region)

   1. Less reactive than alkaline earth metals 

   2. Soft and slippery 

   3. Radioactive 

   4. Elements after uranium are artificial

      List the main groups (families), of the periodic table and describe their unique properties 

1. Alkali metals (group 1)

   1. high ly reactive 

   2. Reacts w/water

   3. Soft metal

   4. Good conductors

   5. Becomes plasma at high temperatures

2. Alkali earth metals (group 2)

   1. Less reactive than group 1 

   2. Harder

   3. Denser

   4. Stronger

   5. Higher melting point

3. Halogens (group 17)

   1. Most reactive of non metals

   2. Combien with most metals to form compounds 

   3. Halogen = salt former 

4. Noble gases (group 18)

   1. Not very reactive

   2. Octet of electrons in outermost shell

5. Inner transition metals - Ianthanides

   1. 4f orbitals 

   2. Less reactive than alkaline earth metals 

   3. Soft, slipper 

6. Inner transition metals - actides 

   1. Radioactive 

   2. Elements after uranium are artificial 

7. Hydrogen 

   1. Family all on its own 

   2. Often resembles halogens 

   3. Very reactive bcs it only has one proton and one electron

1. Describe all the periodic trends discussed in class

   1. Atomic radii (size of an atom) increases ↙

   2. Ionization energy (the energy needed to remove an electron) increases ↗

   3. Electron affinity/electronegativity (the ability of an atom to attract and hold an electron) increases ↗