Isotope & Ions
Define the following terms:
I. Protons
II. Neutrons
III. Electrons
Protons: 1 amu, In nucleus, Positive charge, Define an element
Neutrons: 1 amu, In nucleus, No charge, Involved in isotopes
Electrons: 0 amu, Orbits nucleus, Negative charge, Involved in ions
Determine the number of sig figs in each value:
I. 0.0002010
II. 18,000
III. 2700.30
IV. 0.40600
I. 4
II. 2
III. 6
IV. 5
Define each term:
1. Moles
2. Avogadro's Number
3. Molar Mass
Moles: Unit defined as the amount of material containing 6.02214 x 1023 particles; Think of it as a conversion factor
Avogadro's Number: 6.02214 x 1023; Use when talking about atoms and molecules
Molar Mass: The mass in grams of one mole of a substance; Value seen on the periodic table; Use when talking about grams and mass
1. Accuracy .vs. Precision
2. Mass Number .vs. Atomic Mass
Accuracy - How close a measured value is to the actual value
Precision - How close a series of measurements are to one another
Mass Number - Sum of the number of protons and neutrons in an atom
Atomic Mass - Average mass of atoms of an element; Based on relative abundance of isotopes
Determine the value meaning for each one:
Mega (M), Kilo (k), Deci (d), Centi (c), Milli (m), Micro (weird 'u' shape), Nano (n)
Mega: 106, Kilo: 103, Deci: 10-1, Centi: 10-2, Milli: 10-3, Micro: 10-6, Nano: 10-9
Define each term:
I. Isotopes
II. Ions
Isotopes: Atoms of the same element with different amounts of neutrons (and different masses)
Ions: Atoms of the same element with different amounts of electrons
Solve each problem. Determine the number of sig figs for each final answer.
I. (405.75 x 0.230)
II. (50.0 / 0.37)
I. 3 sig figs; 93.3
II. 2 sig figs; 140
1. A beaker contains 578 mL of water. What is the volume in quarts? (1 quart = 0.946 L)
2. If the density of an object is 2.87 x 10-4 lbs/in3, what is its density in g/mL (1 inch = 2.54 cm, 1 cm3 = 1 mL, 1 lb = 454 g)
1. 0.611 qt
2. 7.95 x 10-3 g/mL
Classify the following as either an element, compound, homogeneous mixture, or a heterogeneous mixture:
I. H2
II. Soil
III. Rust
IV. Soda
I. Element
II. Heterogeneous Mixture
III. Compound
IV. Homogeneous Mixture
Classify the following as either an element, compound, homogeneous mixture, or a heterogeneous mixture:
I. Trail Mix
II. Sugar
III. Br2
IV. Air
I. Heterogeneous Mixture
II. Compound
III. Element
IV. Homogeneous Mixture
Create the isotope notation for each set below:
I. Identity: Boron, Neutrons: 5, Electrons: 5
II. Atomic number: 31, Neutrons: 39, Electrons: 31
I. 10B
II. 70Ga
Solve each problem. Determine the number of sig figs for each final answer.
I. 12.5849 + 2.4
II. 32.567 + 135.0 + 1.4567
I. 3 sig figs; 15.0
II. 4 sig figs; 169.0
1. 18.9 Mega grams = ? micro grams
2. 4.50 x 105 nano liters = ? deci liters
1. 1.89 x 1013 micro grams
2. 0.0045 deci liters
Define the following and give me an example of each:
1. Physical properties
2. Chemical properties
Physical: Those that can be observed without changing the identity of the substance; Color, Density, Phases
Chemical: Properties that describe how a substance changes into a completely different substance; Flammability, Corrosion, Reactivity
Define the following and give me an example of each:
1. Extensive properties
2. Intensive properties
Extensive: A property that depends on the amount of a given substance; Mass and Volume
Intensive: A property that is independent of the amount of a given substance; Density and Temperature
Create the isotope notation for each set below:
I. Identity: Copper, Neutrons: 35, Electrons: 29
II. Protons: 16, Neutrons: 20, Electrons: 18
I. 64Cu
II. 36S2-
Solve each problem. Determine the number of sig figs for each final answer.
I. (320.0 – 22.7) x (3.8111 + 0.160)
II. (200/1.58) + (230 x 21.3)
I. 4 sig figs; 1181
II. 4 sig figs; 5026
How many atoms are in:
I. 25,000 grams of magnesium
I. 144 grams of titanium
I. 6.32 x 1026 atoms of Mg
II. 1.81 x 1024 atoms of Ti
Describe Rutherford's experiment and conclusion
Determined the plum pudding model was incorrect
Proposed that atoms contain a relatively small but high mass center called a nucleus
Shot alpha particles toward a thin foil gold
Expected: Alpha particles either deflected at small degree or have not deflected
Reality: Some alpha particles deflected at small angles, some at large angles, and some all the way back to the alpha particle source
Differentiate between a Theory and a Law
Theory: Based on observations, Have not been proven, Explains why natural phenomenas occur
Law: Based on facts, Have been proven, Summarizes a set of observations about natural phenomenas
Create the isotope notation for each set below:
I. Identity: Chromium, Neutrons: 28, Electrons: 21
II. Identity: Selenium, Neutrons: 40, Electrons: 36
I. 52Cr3+
II. 74Se2-
Solve each problem. Determine the number of sig figs for each final answer.
I. (1.41 - 0.25)(9.1 + 0.91) / (5.4 * 3.80)
II. (3.31 * 4.96)(87.01 / 26) + (54.00 * 1.11)
I. 2 sig figs; 0.57
II. 3 sig figs; 115
How many grams are in:
I. 4.52 x 1028 atoms of zinc
II. 8.01 x 1025 atoms of cobalt
I. 4.91 x 106 grams of Zn
II. 7.84 x 103 grams of Co
Differentiate between JJ Thomson and Robert Millikan
Thomson:
Discovered the electron as: Negatively charged, low mass particle in all atoms
Plum pudding model: Atom is composed of negative electrons in a “soup” of positive protons
Millikan:
Calculated the charge of an electron
Suspended tiny charged droplets of oil between two metal electrodes by balancing downward gravitational forces and upward darg/electric forces
Name the four parts of Dalton's atomic model
Each element is composed of tiny, indestructible particles called atoms.
All atoms of a given element have the same properties that distinguish them from the atoms of other elements.
Atoms combine in simple, whole-number ratios to form compounds.
Atoms of one element cannot change into atoms of another element