Unit 1: The starters

Question 1

What are the groups of the periodic table?

Answer 1

1: Alkali metals
2: Alkaline Earth Metals
3-12: Transition metals
13: Boron group
14: Carbon group
15: Nitrogen group
16: Oxygen group
17: Halogens
18: Noble gases

Question 2

What is the atomic mass of the element, and how is it found?

Answer 2

The atomic mass is the number of grams a mole of the element would be, or the average AMU of that element’s atom.

It is found from a technique called Mass Spectrometry, which weights different isotopes by the abundance on earth.

Question 3

What are some of the main formulas for moles?

Answer 3

1 mole= 6.022 * 10^23 particles
Moles= grams/molar mass

Ideal Gas Equation:
Moles= PV/RT

Question 4

Molarity

Answer 4

Molarity= moles of solute/liters of solution

Example: [NA] means the molarity of sodium atoms, put brackets around to mean molarity.

Question 5

Steps of percent composition:

Answer 5

1. Separate each atom and element from the substance equation.
2. Multiply each element’s atoms by their atomic mass.
3. Add all results into one, and use that to divide each result to find the percent composition
4. Prove by seeing if all add up to near 100%

Question 6

Empirical and molecular formulas

Answer 6

1. Take percentages of each element and multiply by (1 mol (M)/ atomic mass) to find the number of moles present (assume a 100-gram sample for empirical).
2. Divide by lowest mole result for all results to find the number of atoms for each element and make a chemical formula.
3. Multiply the result by atomic mass to find the empirical mass.
4. To find molecular mass, divide the real weight by empirical weight to find scale factor
5. Multiply the empirical formula by the multiplier to find the final result.

Question 7

Coulomb’s Law

Answer 7

E= k(+q)(-q)/r^2
e= energy, k= coulomb's constant, +q= charge of nucleus, -q= charge of electrons, r= distance between charges

Question 8

Photoelectron spectroscopy

Answer 8

The level of energy needed to eject an electron is called the ionization energy (measured in electroVolts= 1.6*10^-19 Joules).

Incoming Radiation Energy= Binding energy + Kinetic energy of an ejected electron

Spectra is a graph about binding energy stuff (check a video)

Question 9

Electron configuration

Answer 9

See sub-shell graph for info

Question 10

Configuration rules:

Answer 10

Pauli Exclusion principle: Two electrons sharing an orbital must spin different ways.
The Aufbau principle: electrons are placed in order of increasing energy
Hund’s rule: Electrons only share orbitals when there are no other options.

Question 11

Predicting ionic charges

Answer 11

+1, +2, varies (3-12), X,+3, -3, -2, -1, 0
silver always +1, and zinc always +2
. Transition metals lose electrons from outer s-subshell first, then d shell.

Question 12

Periodic trends

Answer 12

1. electrons are attracted to protons
   a. the closer an electron to the nucleus, the more strongly it is attracted.
   b. The more protons in nucleus, the stronger an electron is attracted.
2. Electrons repelled by other electrons.
3. Completed shells are very stable. Atoms will do anything to obtain them.

Question 13

Atomic radius

Answer 13

The distance from nucleus to valence electrons.

Question 14

Ionization energy

Answer 14

second ionization energy is greater than the first

When shell is empty, it takes a lot of energy to remove one from full shell, because full is stable.

Question 15

Electronegativity

Answer 15

how well an atom’s nucleus attracts the electrons of another.

Affected by 2 factors:

1. The smaller the atom, the higher the electronegativity
2. The closer it is to a full energy level, the faster it will get it, so higher electronegativity

Question 16

Electron affinity

Answer 16

Energy change that occurs when electron is added to an atom in the gaseous state. This is opposite of ionization as it releases energy.