Transcript Chemistry test Review

Chemistry test Review
Crossword Puzzle answers –
Across
3. Groups
4. Periods
9. Noble gases
12.Metalloids
13.Number
16.Valence electrons
21.Reactivity
22.Transition
24.Properties
25.Neutral
26.metals
Crossword Puzzle Answers - Down
1. Ductility
2. Proton
5. Element
6. Conductivity
7. Semiconductors
8. Halogens
10.Atom
11.ion
14.Electron
15.Malleable
17.Negative
18.Alkali
19.Mass
20.Brittle
21.nucleus
Study Guide Answers
1. Who were the three men we discussed who
contributed to the current Atomic Theory (what
we know about atoms)? What did each man
contribute?
• Democritus
–
•
Thomson
–
•
First determined there was such a thing as an atom
Discovered the negatively charged particles we now
call electrons
Rutherford
–
Discovered that there is a positively charged
nucleus at the center of the atom
2. Describe, in detail, the three part of the
atom (size, location, charge, etc…)
• Proton
– Positively charged, large particles (1amu)
found in the nucleus at the center of the
atom
•
Neutron
– Neutrally charged, large particles (1 amu)
found in the nucleus at the center of the
atom
•
Electron
– Negatively charged, small particles (0 amu)
found in electron clouds that circle the
nucleus
3. What unit is used to measure the mass
of an atom or its parts? Is this the same
general unit we use for everything else?
Why/why not?
• Amu – Atomic mass unit
• It is not the same as a gram
– Because atoms and their particles are way
too small to use the normal mass
measurement system so scientists had to
come up with a new way to measure their
mass
4. Explain the difference between atomic
number and atomic mass
• Atomic number
– Describes how many protons are in the
nucleus of an atom
– Also describes the number of electrons in a
neutral atom
•
Atomic mass
– Describes the sum of the number of protons
and neutrons in the nucleus of the atom
5. Write your own definition for
element and pure substance
(do not use the book
definition!!!!)
6. Why can’t two elements have the exact
same properties?
- because they would no longer be
different if they had exactly the same
properties
- two elements can share some similar
properties, but they must have at least
one property different from each other in
order to be different from each other
7. If you were given samples of two different
elements, but they were not labeled, how
could you determine what they are?
• Density
• Color
• Melting point
• Boiling point
• texture
8. Describe the three types of elements
• Metals
–
Shiny, ductile (pulled into wires), malleable
(hammered into thin sheets), good conductors of
heat and electricity
•
•
Nonmetals
–
Dull, brittle (shatter easily), poor conductors
•
•
To the left of the zigzag line on the periodic table
To the right of the zigzag line on the periodic table
Metalloids
–
–
Also known as semi-conductors
Have properties of both metals and nonmetals
•
On the zigzag line on the periodic table
9. What was different between the periodic
tables Mendeleev and Mosely created?
Whose periodic table do we still use
today?
• Mendeleev used increasing atomic mass
to organize the table
– There were gaps in some places
•
Mosely used increasing atomic number
– This is the organizational method we still
use today
10. What type of element is Rhenium (Re),
atomic number 75? How do you know?
• It is a metal
– It is located within the transition metals
– It is to the left of the zigzag line
11. What pieces of information can you
obtain from each entry in the periodic
table?
• Atomic number
– # of protons in the atom
•
Atomic mass
– # of protons and neutrons in the atom
•
•
Element name
Element (chemical) symbol
– One or two letters
12. Find Terbium (Tb) on the periodic table.
How many protons are in one atom of
Terbium? Electrons? Neutrons?
• Atomic # is 65, atomic mass is 159
• Protons – 65
• Electrons – 65
• Neutrons - 94
13. How many valence electrons would an
atom of Astatine (At) have? How do you
know?
• At would have 7 valence electrons
– It is a member of the halogen group (group
17)
14. Is Astatine a reactive element or not?
How do you know?
• It is highly reactive
• Because it is in group 17 and has 7
valence electrons
– Group 17 elements want to quickly fill up
their outermost orbital and have 8 valence
electrons to be “happy”
15. What are the names of the rows and
columns in the periodic table? How
many of each are there?
• Horizontal rows are called periods
– There are 7 periods
•
Vertical columns are called groups or
families
– There are 18 groups