Name: _______________________________ Date: __________________ Hour: __________________
Vocabulary
Chapter 17.1-17.4: Atoms and the Periodic Table
Read the following passage carefully and use context clues to determine the
meaning of the underlined words. Italicized words may be unfamiliar as well- use
context clues or look them up as needed.
You know that atoms make up the matter around you, from stars to steel to
chocolate ice cream. You might think that there must be may different kinds of atoms to
account for the huge diversity of matter. To date, we know of slightly more than 100
distinct atoms. Of these, about 90 are found in nature- the remaining atoms have been
created in a laboratory. Elements are made of atoms- pure gold, for example, is an
element- it contains only gold atoms.
Similarly, one of the gases in air is nitrogen,
an element also. Elements are organized
and listed in a chart called the periodic
table.
Each element in the periodic table is
designated by its atomic symbol. For
example, the atomic symbol for carbon is C,
and the one for chlorine is Cl. In many
cases, the atomic symbol for an element is
derived from its Latin name. Gold, for
example, has the atomic symbol Au after its
Latin name, aurum.
How do atoms of one element differ from another element? Each element is
identified by its atomic number. Hydrogen, with one proton per atom, has an atomic
number of one. Helium, with two protons in its nucleus, has an atomic number of two…
and so on. An element has a definite number of protons, but the number of neutrons it
contains may vary. For example, most iron atoms (atomic number 26) have 30
neutrons, but a very small percentage have only 29 neutrons- this is called an isotope.
How can we tell isotopes apart? We identify isotopes by their mass number. An
iron isotope with 26 protons and 30 neutrons is therefore iron- 56, and an iron isotope
with 26 protons and 29 neutrons is iron- 55. The mass number – atomic number =
number of neutrons. The total mass of an atom is called its atomic mass. This is the
sum of the masses of all the atom’s components (electrons, protons and neutrons). A
special unit has been developed for atomic masses. This is the atomic mass unit, the
amu. One atomic mass unit is slightly less than the mass of one single proton. The
atomic masses listed on the periodic table are in atomic mass units.
1. Element
a. I think the word element means: _________________________________
___________________________________________________________
b. Have you heard the word element used before? ____________________
Where? ____________________________________________________
c. The definition of element a is ___________________________________
___________________________________________________________
d. I could use element in the following sentence (situation): ______________
___________________________________________________________
___________________________________________________________
2. Atomic Symbol
a. I think the word atomic symbol means: ____________________________
___________________________________________________________
b. Have you heard the word atomic symbol used before? _______________
Where? ____________________________________________________
c. The definition of atomic symbol is ________________________________
___________________________________________________________
d. I could use atomic symbol in the following sentence (situation): _________
___________________________________________________________
___________________________________________________________
3. Atomic Number
a. I think atomic number is: _______________________________________
___________________________________________________________
b. Have you heard atomic number used before? ______________________
Where? ____________________________________________________
c. the definition of atomic number is: _______________________________
___________________________________________________________
d. I could use atomic number in the following sentence (situation): ________
___________________________________________________________
___________________________________________________________
4. Isotope
a. I think the word isotope means: _________________________________
___________________________________________________________
b. Have you heard the word isotope used before? _____________________
Where? ____________________________________________________
c. The definition of isotope is _____________________________________
___________________________________________________________
d. I could use isotope in the following sentence (situation): ______________
___________________________________________________________
___________________________________________________________
5. Mass Number
a. I think the word mass number means: ____________________________
___________________________________________________________
b. Have you heard the word mass number used before? ________________
Where? ____________________________________________________
c. The definition of mass number is ________________________________
___________________________________________________________
d. I could use mass number in the following sentence (situation): _________
___________________________________________________________
___________________________________________________________
Words I didn’t know
Definition
___________________: __________________________________________________
___________________: __________________________________________________
___________________: __________________________________________________
___________________: __________________________________________________
___________________: __________________________________________________
Questions: Answer the following questions (COMPLETE SENTENCES!)
1. How many types of atoms can you expect to find in a sample of any element?
2. Distinguish between an atom and an element.
3. If atoms are mostly empty space, why cant we walk through walls?
4. Name and describe the three subatomic particles found in an atom.
5. What kind of force prevents atoms from squishing into each other?
6. What is an atomic number? What role does this number play in the periodic table?
7. Distinguish between atomic number and mass number.
8. Distinguish between mass number and atomic mass.
9. How do you calculate the atomic mass of an element? What effect do isotopes of a
given element have on the atomic mass calculated for that element?
10. A cat strolls across your backyard. An hour later, a dog with its nose to the ground
follows the trail of the cat. Explain what is going on in terms of atoms.
11. If all the molecules of a body remained part of that body, would the body have any odor?
12. In what sense can you truly say that you are part of every person around you?
13. Why are the atomic masses listed on the periodic table not whole numbers?
14. If an atom has 43 electrons, 56 neutrons, and 43 protons, what
is its approximate atomic mass? What is the name of this
element?