Chem Midterm Pt 2.

An isotope is an atom of the ____ element with a different number of _____.

same; neutrons

What is the mass of this isotope? U-236

236g/mol

One atom has 40 protons and a mass of 92, the second atom has 40 protons but a mass of 87. What is this atom’s identity and why are the mass’ different?

They are isotopes of Zr, xzirconium

What is the average atomic mass of hydrogen if Hydrogen-1 is 99% abundant, Hydrogen 2 is 0.5%, and Hydrogen-3 is 0.5%.

1.01 g/mol

(1×99%)+(2×0.5%)+(3×0.5%)

What is the average atomic mass of Lithium if Lithium-7 is 92.5% abundant and Lithium 6 is 7.5% abundant?

6.93 g/mol

(7×92.5%)+(6×7.5%)

who was known for the thinking substances were composed of different portions of what the earth was made of?

Aristotle/Plato

Who though the world was made of indivisible particles called “atomos” (cutting rock)

Democratus

Who studied the weight of element and compound, noticed that matter always combined to form a whole number ratio based on weight/ volume (proposed first atomic theory?

John Dalton

Who discovered electron with his Cathode Ray Tube Experiment, found positive and negative charges with his model Plum Pudding?

JJ Thomson

Who discovered the nucleus of an atom and atoms were mostly empty space, Gold Foil experiment (atoms were small and dense) + inside/- outside

Ernest Rutherford

Who thought that e- moves in fixed energy orbits (Bohr model like planets)

Niehls Bohr

where are protons located?

in the nucleus

where is the neutrons located?

in the nucleus

where are electrons located?

Anywhere outside of the nucleus (electron cloud)

Who created the mathematocal equation to find the position of e- and quantum mechanics?

Erwin Schrodinger

What does Rutherford find out with the Gold Foil experiment?

atoms are mostly empty space/nuclei is super small/ if particles hit + they will repel

Why is the Bohr model inaccurate?

NOT ACCURATE, does not spin around the orbitals

What is the atomic number of Vanadium?

23

What is the element symbol for sodium?

Na

what is the name of the element Sn?

Tin

what is the atomic mass of Pt?

195.08 g/mol

What changes the identity of the element?

the # of protons

How many protons and electrons are in Na?

11 p+ 11e-

How do you find how many neutrons are in a element

atomic mass- # of protons/atomic number = # of neutrons

How many neutrons are in Mn?

30 n

How many neutrons are in Y?

50 n

What are the rules to drawing Bohr models?

1. write the element symbol in the middle

2. find the # of rings/energy levels

3. follow 2, 8, 8 rule (1st ring:2; 2-infinite:8)

What does the Bohr model help us find?

the number of valence electrons a element has

What are isotopes?

atoms of the same element with a different # of neutrons

Who is the biggest atomic radius? (sulfur, strontium, oxygen)

Strontium, Sulfur, Oxygen

Who has the biggest electronegativity?(sulfur, strontium, oxygen)

Oxygen, Sulfur, Strontium

Which one is the “periods”

the horizontal rows

Which are “groups”?

vertical columns

Properties of metal?

good conductors of heat/electricity, lustrous, malleable, ductile, solid at room temp

Properties of nonmetals

poor conductors of heat/electricity, brittle, dull

Properties of Metalloids

Fair conductor of heat and electricity, looks metallic but brittle, mostly forms anions (more closely related to nonmetals)

What is the name of Family 1 A and some of its properties?

Alkalai Metals; 1 ve-, explosive with water to form hydroxides, extremely soft, can cut with a knife; more reactive as you move down; needs to be in oil

What is the name of Family 2A and its properties?

Alkalai Earth Metals; 2ve-, reacts with water to form hydroxide; soft (not as much as Family 1A)more

What is the name of Family 7A and properties?

Halogens; 7 ve-, react with hydrogen to form halide; reacts readily; more reactive as they move up

What is the name of Family 8A and properties?

Noble Gases; 8ve-, already stable, do NOT bond; more dense moving down, extremely useful in nature.

Lowest to highest atomic radius (H, Fr, He)

He, H, Fr

What is electronegativity?

a measure of how much an atom attracts e- to itself (homeless wanting money)

What is ionized energy?

the energy required to remove na e- from an atom

What orbital is this

S orbital

What orbital is this?

p orbital

what orbital is this?

d orbital

what orbital is this?

f orbital

What are the 3 rules for electron configuration?

Aufbau, Pauli, Hund’s

What is Aufbau principle?

electrons fill orbitals in order of increasing energy (start with 1s)

What is the Pauli exclusion principle?

no 2 e- in the same atom can have the same spin, 2 opposite parrallel spins

What is Hund’s rule?

When filling orbitals within a subshell, electrons will occupy each orbital before pairing up

How many orbitals and electrons are in subshell s?

1, 2e-

How many orbitals and electrons are in subshell p?

3, 6e-

How many orbitals and electrons are in subshell d?

5, 10e-

How many orbitals and electrons are in subshell f?

7,14 e-

How to write Oxygen’s electron configuration?

1s²2s²2p⁴

How does electronegativity, atomic radius, and ionized energy related?

The more electronegativity the element is, the more ionized energy it needs to remove the electron. The elements with higher electronegativity have a smaller radius

Is magnesium a cation or anion and oxidation state?

cation, Mg²⁺

Lewis dot structures show what?

lone pairs, bonds, and lone e-

What does a compound contain?

nonmetal and metal

How are Ionic Compounds stuck together?

electrostatic force

Is there a tangible bond between atoms

no, held together by electrostatic force

Does the dots get drawn on the metal or nonmetal when doing bracket notation?

Nonmetal

When do you need to write a Roman numeral?

when the metal is a transition metal

Properties of Ionic compounds

strong/stable, dissolves in water, HIGH melting and boiling point, conducts electricity and heat

Name of K₂S

Potassium Sulfide

Name of CoAs₂

Colbalt VI Arsenide