Subatomic Particles and The Periodic Table
2.5 The Structure of the Atom
Millikan Oil Drop Experiment (Elemental Charge)
Introduction to Subatomic Particles and Nuclide Symbols
Objectives
1. Describe the Millikan oil drop experiment and how gravity and
electrical forces were used to determine the electron's charge.
2. Provide mass, charge and location information for all three
subatomic particles inside an atom (Protons, Neutrons and Electrons)
3. Determine proton or electron numbers for neutral atoms
4. Write nuclide symbols for neutral atoms and determine nuetron
numbers from given nuclide symbols and information available
on the periodic table (Atomic number and Atomic mass)
5. Use nuclide symbols to determine numbers of protons, neutrons and
electrons for specified atoms.
6. Know how the following terms apply to the periodic table
Group, Period, alkali metals, alkaline earth metals
Metals, metaloids, non-metals, halogens, noble gases
7. List properties of alkali metals, alkaline earth metals, halogens,
noble gases. metals metaloids and non-metals
8. Know what it means to say that elements in the same group have
similar chemical and physical properties.
The Periodic Table: Classification of the Elements
7.1 In Coulombs, what are the charges of protons and electrons? How do they compare? How do they differ?
7.2 In the Milikan Oil Drop experiment, if the applied electrical force is too small, how does the oil droplet respond?
7.3 How many electrons would be required to equal the mass of a single proton?
7.4 Use your periodic table to determine the number of protons and electrons for each of the following neutral atoms:
a. chlorine atom b. cobalt atom c. potassium atom d. argon atom e. iron atom f. silver atom g. tungsten atom
7.5 What is the "atomic mass" and where is it found on the perioodic table? What is the "atomic number" and where is it found on the periodic table?
7.6 For each of the following neutral nuclide symbols, list the numbers of protons, neutrons and electrons.
7.7 For each of the following nuclide symbols list the numbers of protons, neutrons and electrons.
7.8 Why are eleectrons not usually included in an atom's atomic mass?
7.9 How many protons and neutrons are found in an argon-40 nucleus?
7.10 How many protons and neutrons are found in a carbon - 13 nucleus?
7.11 List the common physical and chemical properties of Metals, Metaloids and Non-metals
7.12 Identify the element that is an alkaline earth metal in period 4
7.13. Identify the element that is a halogen in period 5
7.14 Identify the period 3 element that is a metaloid
7.15 Which of the following elements would have chemical and physcical properties similiar to sulfur?
Phosphorus, Nitrogen, Oxygen, Fluorine, Chlorine, Bromine, Selenium, Arsenic
7.16 Protons are found closely packed into an atom's nucleus. Since they are all positively charged they repel each other strongly.
What keeps the protons from pushing away from eachother and exploding the nucleus?
Click and drag below for answers:
7.1 Proton: + 1.602 x 10-19 C Electron: - 1.602 x 10-19 C They are equal but opposite in sign
7.2 The applies electric force pulls against gravity. If the electric force is too small, gravity wins and the droplet falls
7.3 Massproton = 1.6726 x 10-27 kg Masselectron = 9.10 x 10-31 kg It would require approximately 1840 electrons to equal the mass of a proton
7.4 Since the question specifies "Neutral" atoms, we know the numbers of protons and electrons are equal. We get the proton count
from the elements "atomic number" on the periodic table.
a. 17 protons and electrons b. 27 protons and electrons c. 19 protons and electrons d. 18 protons and electrons e. 26 protons and electrons
f. 47 protons and electrons g. 74 protons and electrons
7.5 The atomic mass of an element is usually found beneath the element's symbol on the periodic table. It is the average mass of an atom in amu
units and is also the molar mass of the element in grams (same number...different meaning)
The atomic number of an element is usually found above the element's symbol on the periodic table. It tells us the number of protons in
the atom's nucleus.
7.6 Since all are neutral species, electons = protons
a. 5 protons 10 - 5 = 5 neutrons b. 5 protons 11 - 5 = 6 neutrons c. 6 protons 12 - 6 = 6 neutrons
d. 6 protons 13 - 6 = 7 neutrons e. 8 protons 16 - 8 = 8 neutrons f. 8 protons 17 - 8 = 9 neutrons
g. 8 protons 18 - 8 = 10 neutrons h. 17 protons 35 - 17 = 18 neutrons i. 17 protons 37 - 17 = 20 neutrons
7.7 Post your answers in the Week 2 discussion forum.
7.8 The mass of an electron is very small in comparison to protons and neutrons. Consequently, electron masses usually aren't included in atomic masses.
7.9 Argon-40 has a total of 40 protons and neutrons. From the periodic table, we obtain argon's atomic number (18). Thus argon has 18 protons and
40 - 18 = 22 nuetrons.
7.10 Carbon-13 has a total of 13 protons and neutrons. From the periodic table, we obtain carbons's atomic number (6). Thus carbon-13 has 6 protons and
13 - 6 = 7 nuetrons.
7.11 Metals: Good conductors of heat and electricity, malleable (What does this mean?), Ductile (What does this mean?) Shiny and
metals lose electrons when they undergo chemical change
Non- Metals: depending on the element, may be solid, liquid or gas, poor conductors of heat and electricity (Insulators),
non-metals gain electrons when undergoing chemical change
Metaloids: Mixed properties depending on the element. Silicon can be both electrically conductive and non-conductive depending on the
situation. Consequently, it is useful in electronics where the ability to be both is useful.
7.12 Calcium
7.13 Iodine
7.14 Silicon
7.15 Oxygen and Selenium are in the same checmical group as sulfur and are therefore expected to have similar chemical and physical properties.
7.16 Neutrons are required in the nucleus to keep protons from pushing away from themselves. The neutrons add what's known as a
strong nuclear attraction (or force) that "glues" the nucleus together.