Download File

What are Atoms Made of?
While Viewing the Program
1. What is an element?
A pure substance composed of atoms with the same atomic number.
2. How many elements are there?
114
3. Why can’t we look at atoms?
They are really small
4. What kind of evidence is used to support the theory that matter is composed of atoms?
X-ray diffraction data, radiation experiments (indirect evidence)
5. Define the following:
a)
Proton
Sub-atomic particle with a positive charge
b)
Neutron
Sub-atomic particle with no charge
c)
Electron
Tiny sub-atomic particle with a negative charge
d)
Ion
Charged atom or group of atoms (uneven number of protons and electrons)
e)
Isotope
Atoms with the same number of protons but different neutron numbers.
6. How much of the space occupied by an atom is the nucleus?
Not much (about 1/10000)
a)
What is an atom mostly made up of?
Empty space!
7. What kind of particles did Rutherford fire at the sheet of gold leaf?
Alpha particles (helium nuclei)
a)
What kind of charge would these particles have?
positive
b)
What was he expecting?
Nothing!!!!
c)
What actually happened?
Some alpha particles bounced back and many were deflected.
8. What did Niels Bohr discover about where electrons can be found?
They exist in certain energy levels called shells.
a)
What did the colours in emission spectra represent?
Wavelengths corresponding to light given out when electrons moved from a higher to
lower shell.
9. What is the outer shell of electrons called?
Valence shell
a)
Why is it important?
The valence electrons are involved in chemical reactions.
10. Why did Mendeleev call his table “Periodic”?
Because properties repeated periodically (ie. Elements in the same column have similar
chemical properties)
a)
There were gaps in the table. What did he predict about these gaps?
He predicted properties of undiscovered elements and within 20 years they were
discovered.
11. Explain the following and provide an example for each:
a)
Chemical Symbol
One or two letters used to represent element eg. Sodium-Na
b)
Atomic number
Number of protons in atom
c)
Atomic weight
Relative weight compared to carbon-12
12. Complete the following table
Group
Number of electrons in outer shell (Valence electrons)
Alkali metals
1
Alkaline Earth metals
2
Noble gases
2 or 8
Halogens
7
13. What is a period?
A row of the periodic table
14. Complete the following table. Max # of e- = 2 x (shell number)2
Shell number
Number of electrons in shell
1
2
2
8
3
18
4
32
5
50
Octet rule: a shell is stable (unreactive) once there are 8 e- in it
a) Explain how you find the answer.
See above
15. Why is an element with only one electron in its outer shell very reactive?
If it loses it, it will have a noble gas e- configuration
a)
What about an element that only needs one more electron to fill its outer shell?
It will gain an electron
b)
Give an example for each of the above.
Group 1 elements lose electrons, group 7/17(halogens) will gain an electron
16. What happens when Sodium and Chlorine react?
Sodium loses an electron to chlorine
a)
How is this different from a mixture?
Mixtures are not chemically combined
17. What is the difference between ionic bonding and covalent bonding?
Ionic is ions stuck together, covalent = shared electrons
18. What is a cation?
A positively charged ion
19. An anion?
A negatively charged ion
20. Write a chemical equation for what happens when:
a)
Potassium combines with chlorine to produce Potassium Chloride
2K(s) + Cl2(g)  2KCl(s)
b) The combination of Carbon with oxygen to produce Carbon dioxide
C(s) + O2(g)  CO2(g)
21 What do you think the di in dioxide stands for?
2
BrainPOP - Periodic Table
Name
Watch the Periodic Table movie at http://www.BrainPop.com/ to complete this worksheet.
1. The Periodic Table of Elements is a list of all the chemical elements that occur
in the
__universe_____________. It categorizes elements according to the properties of their
__atoms________, which are the smallest unit of an element.
2. Atoms are made up of a __nucleus___________ composed of protons and neutrons
and a number of electrons orbiting in shells or _orbitals____________.
3. It is the number of protons, neutrons, and electrons in an element’s atoms that
determines its __properties____________. The configuration of the three particles is
the only thing that makes one element ___different____________ from another.
The modern table organizes elements so it is easier to see how elements
are
__related___________ to each other.
The elements are listed by the
___atomic number__________
___________, or the number of protons in the atom’s nuclei. The table also lists the
elements _symbol____________, name, and _atomic__________ __mass_______.
4.
5. Each shell can hold only a certain number of __electrons___________. The number
Word List:
92
118
atomic mass
atomic number
atoms
bond
chemical
color
different
electrons
giving up
groups
nucleus
orbitals
periods
properties
related
sharing
symbol
universe
valence
of electrons in an atom’s outer shell plays an important role in that atom’s properties
determining what other kinds of atoms it can __bond_________ with. Atoms bond
together in molecules by either
__giving
up_________
___
or
__sharing_________
electrons.
__Valence______________ describe the number of electrons in the outer shell.
6. Because atoms with similar numbers of electrons in outer shells behave in similar ways, you can also
read the table in vertical rows called __groups__________. Elements in groups have similar
__chemical___________ properties.
The periodic table is also organized by ___colour__________ into different categories. These
categories are organized by properties of the elements.
7.
8. Some periodic tables may show elements all the way up to number 118 , but any element over
Uranium number 92
nature and must be made in a lab.
is too unstable to occur in
Try the quiz to help you answer these questions ...
What do you get when you chemically combine chlorine gas and sodium? A. Table salt B. Car wax C. A bad monster
Which of the following is a noble gas? A. Hydrogen
B. Helium
C. Carbon
How do you find the atomic number of an atom? A. # of Protons B. # of Neutrons
C. # of Electrons
What are metallic elements generally known for? A. Liquid at room temp B. Conductivity C. Generosity
Where would you find the element copper? A. Steak knives
What is the smallest unit of a pure element? A. Atom
B. Telephone wires
B. Neutron
C. Vacuum tubes
C. Molecule
What do we call an atom in which the number of protons is not equal to the number of electrons? ion
How is the Periodic Table organized? A. Rows and aisles
B. Periods and groups
When was the first modern Periodic Table developed? A. 1066
C. Lines and boxes
B. 1492 C. 1871
What is a molecule? A. Particles that are fragile B. Atoms that have bonded
C. Synthetic car seat covers
Who is credited with coming up with the modern Periodic Table? A. Einstein
B. Bohr
How are elements listed in the Periodic Table? A. Year discovered
B. Atomic Number
C. Mendeleyev
C. Physical beauty
What are Atoms Made of?