Chemisty unit 2

atomic structure, mole, electrons, periodic table

Where did the idea of the atom originate?

Greece, 400 BC

What did JJ thomson discover about the atom?

Found electrons

What did Rutherford discover about the atom?

the nucleus

What the atom mostly made up of?

the electron cloud with mostly empty space

what is the relative mass of protons?

1

what is the relative mass of neutrons?

1

what is the relative mass of electrons?

basically nothing

The number of protons determines the ______

element

What is an atomic number?

number of protons

Atoms are electrically neutral meaning

protons = neutrons

mass number =

protons + nuetrons

what is an isotope?

atoms of the same element with different #’s of neutrons

What is the isotopic symbol for Carbon 14?

¹⁴C

What is average atomic mass?

weighted average of the isotopes of an element and their relative abundance in nature

If 20.0% of boron is ¹⁰B and 80.0% of boron is ¹¹B, what is the average atomic mass? (Know how to solve the problem)

10 x .20 = 2.0

11 x .80 = 8.8

10.8

Check periodic table to ensure answer is correct

What is a mole?

The SI unit for the amount of a substance

What is the SI unit for elements?

atoms

What is the SI unit for ionic comounds?

formula unit

What is the SI unit for molecular compound?

molecule

What is avagadros number?

6.022 × 10²³

1 mole of different substances have same number of particles but (do / dont) have the same volume/mass

dont

mass of one mole is same as _________

average atomic mass on periodic table

How many mol N are in 98.7g N?

98.7g N (1 mol N / 14.01 g N) = 7.04 mol N

How many atoms AI are in 4.52 mol AI?

4.52 mol AI ( 6.022 × 10²³ / 1 mol ) = 2.72 × 10²⁴

What is a quantum number?

where an electron probably is 90% of the time

What does n represent?

The principle quantum number or energy level

What is the principle quantum number?

How far on average an electron is from the nucleus of an atom

What does L represent?

angular momentum number or orbitals

What is the angular momentum number?

the shape of a possible path of an electron may take

How many electrons can an orbital hold?

2 electrons

How many electrons does an s orbital hold?

2 electrons

How many electrons does an p orbital hold?

6 electrons

How many electrons does an d orbital hold?

10 electron

How many electrons does an f orbital hold?

14 electrons

What does m₁ represent?

magnetic quantum number

What is the magnetic quantum number?

describes where orbitals are in relation to outer orbitals/nucleus

what does the aufbau principle state?

electrons fill lowest energy orbitals first

what does the pauli exclusion principal state?

each orbital can hold up to 2 electrons and must have opposite spins

What does m_s represent?

Electron spin

What is electron spin? ( i dont actually think we need to know this but its gynther)

either +1/2 or - ½

What is the order of orbital filling?

1s 2s 2p 3s 3p 4s 3d 4p 5s 4d 5p 6s…

What is hund’s rule?

lowest energy level is the one with the max number of unpaired electrons allowed by pauli exculsion

The horizon tal rows on the periodic table are called ______

periods

the atomic number _______ as you move across and down

increases

Period number corresponds with ______

orbitals

The vertical columns on the periodic table are called _____

groups or families

What is the group based on?

number of valence electrons

what are valence electrons?

number of electrons in the outermost energy level

Group A are all ___________

representative elements

Group B are all _________

transitional medals (Sn, Pb….)

Where is group B found?

D-block

Group 1A is also known as ________

alkali metals (very reactive)

Group 1B is also known as ________

alkaline earth metals

Group 7A is also known as ________

hallogen (very reactive non metals)

Group 8A is also known as ________

noble gases (very unreactive)