Significant Figures
How many significant figures in 1.0500
5
How many inches are in 4 ft.
12 in = 1 ft
48 in
What are the 3 subatomic particles in an atom?
Neutron, Electron, Proton
When does an electron release energy?
When it goes back to its original orbital after getting excited.
Describe the first atomic model.
Dalton's model: A hard sphere
Have many significant figures are in 0.00000000012050
5
Each dimensional analysis problem has taken you 1.5 minutes to complete. How many dimensional analysis problems could you complete in 6 weeks of chemistry class?
1 period = 50 min
50/1.5 = 33.3
33.3*5 = 166.66
166.66*6 = 1000
1000 dimensional analysis problems
What is the charge of the nucleus. Explain
Positive because Protons are positive and Neutrons have no charge.
Write the electron configuration of an excited atom of Phosphorus.
2-7-6
Describe the Wave-Mechanical model, in your own words.
The wave mechanical model has a positively charged nucleus, with an electron cloud around it, because we don't know the exact location of the electrons.
Solve the following equation to the correct number of significant figures: 0.1204/0.00004
3000
Find the density of 4000 mg of Mg metal in 4 ml of water in the units g/cm^3
1000 mg = 1 g
1 ml = 1 cm^3
1 g/cm^3
Using your CRT, determine the number of Protons, Neutrons, and Electrons in a neutral atom of Sulfur-34.
16 protons, 18 neutrons, and 16 electrons
1) C 2) V
3) Ne 4) Sb
3) Ne
What was Rutherford's experiment and what did he discover?
He shot Alpha particles into gold foil and found out that the atom is mostly empty space with a positively charged nucleus. The alpha-particles mostly went through except for when it bounced off when it hit the center.
Answer: 9.3 which has 2 sig-figs
A car is traveling down a highway at a speed of 52 miles per hour. What would this speed be in units of meters per second?
1 mile = 1.609 km 1 km = 1000 m
1 hour = 60 min 1 min = 60 sec
52/1.609 = 32.3 meters
60*60 = 120 sec
Answer: 32.3 meters/120 sec
Determine the number of neutrons in a neutral isotope of Potassium-41.
22 neutrons
What color would be emitted if an electron relaxed from the fourth shell to the third shell? Explain
1) Red. 2) Yellow
3) Blue. 4) Purple
Red, because it was a small jump back to its original shell.
List the 5 atomic models in order.
Daltan's Model, Thomson's Plum Pudding Model, Rutherford's Model, Bohr's Planetary Mode, Schrodinger's Wave Mechanical Model
Solve the following in the correct number of sig-figs: [(40.64+0.213+65.1) * 41)
106.0*41 = 4300
John can read 15 pages of a book every 45 minutes. How many hours will it take him to read the entire 200 page book?
1 hr = 60 min
45/60 = 0.75 hr
200/15 = 13
13*0.75 = 10 hrs
They have 7 protons and electrons. Nitrogen-14 has 7 neutrons and Nitrogen-15 has 8 neutrons.
Write an electron configuration for ground state Aluminum and excited state Aluminum.
Ground State: 2-8-3
Excited State: 2-7-4
Describe how the atom changed over time.
The atom started off as a hard sphere, and then Thompson discovered that there are small negatively charged particles in an atom. Through Rutherford's gold foil experiment, we determined that the atom was mostly empty space except for a postively charged nucleus. Bohr then discovered that the electrons were in shells around the nucleus. Finally, the modern atom has a positively charged nucleus with an electron cloud.