Download Atom/Elements Study Guide

Atom/Elements Study Guide
Basic Concepts
1. The atom is the smallest particle that cannot be broken down by ordinary means; it is
the building block of all matter.
2. A neutral atom is one that carries no charge because the protons (+) and electrons (-)
are equal, therefore balancing each other out.
3. A stable atom is one where the number of protons and neutrons are close and the atom
does not decay
4. A radioactive atom is an isotope that will decay, it is not stable
5. Compare the three types of radioactive decay.
1. Alpha decay – the atom ejects two protons and two neutrons (i.e., the nucleus
of a Helium atom)
2. Beta decay – a neutron splits into a proton and an electron
3. Gamma decay – the nucleus emits pure energy in the form of gamma rays
6. Match
Strong nuclear force holds the protons together in the nucleus.
Weak force is used when an atom decays; it helps the stray neutrons break apart.
Electromagnetic forces keep the atom together.
7. Electromagnetic spectrum is all possible light; the visible spectrum is just the light we
can actually see with our eyes.
8. A spectroscope is a device that spreads the light into its different colors.
Atomic Structure
1. What is the electrical charge and position in the atom for each of the subatomic
particles?
1. Electron - negative charge; located in a “cloud” rotating around the nucleus
2. Proton – positive charge; located in the center or nucleus of the atom
3. Neutron - no charge; located in the center or nucleus of the atom
2. What subatomic particles are in the nucleus of the atom and what is the charge of the
nucleus?
Protons and neutrons so the charge of the nucleus is positive
3. The atom is composed mostly of empty space.
4. Where is most of the mass of the atom located? In the nucleus
5. How many electrons can exist in the first shell? The second? 2, 8, 8,18
6. Which two subatomic particles have approximately the same mass?
Neutrons and protons
7. Atoms with the same number of protons but different numbers of neutrons are called
isotopes.
Periodic Table
1. Elements in the periodic table are arranged by atomic number OR the number of
protons.
2. T or F An elements properties can be predicted from its location in the
periodic table.
3. The atomic number of an element is equal to the number of protons.
4. How can you find the number of neutrons in an atom? Atomic mass – atomic #
5. What makes one element different from another? The number of protons.
Using the Periodic Table
1. Draw a Bohr model of the element Chlorine, Cl.
2. Draw Bohr models of Carbon isotopes with atomic masses of 11, 12, and 13amu.
Extra Questions
1. What force prevents atoms from squishing into one another? Electromagnetic
2. Compare atomic number and atomic mass number. Atomic number is the number of
protons. The atomic mass number represents all of the matter in the atom – the whole
numbers represent the sum of protons + neutrons. The decimal represents the mass of the
electrons.
Atomic number = # of protons
Atomic Mass = protons + neutrons
3. If an atom has 43 electrons, 56 neutrons, & 43 protons, what is the approximate atomic
mass? What is the element? Atomic mass = 43 + 56 = 99 which is Tc
4. Why are the atomic masses in the periodic table not whole numbers?
They are averages of the masses of atoms of each element. There can be a variety of
isotopes, atoms with the same number of protons and electrons but different numbers of
neutrons.