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Atom/Elements Study Guide
You need to make sure you review the Resources that have been posted on the blog in the
homework section for the past three classes…all these are solid study aids!
Listed below are some of the key concepts and questions you should be able to answer – the quiz
format will include some objective questions, some essays, diagrams, as well as cartoons, and some
performance tasks
Basic Concepts
The atom is the smallest particle that cannot be broken down by ordinary means; it is the building block of all
matter.
A neutral atom is one that carries no charge because the protons (+) and electrons (-) are equal, therefore
balancing each other out.
Elements are the simple building blocks of all substances, each element of the 92 naturally occurring elements
are made of a unique atom with a different number of protons.
Chemical compounds are created when different elements react and combine chemically.
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ANALOGY TIME! Think of elements like the LETTERS of the alphabet, some letters can combine to
form WORDS which would be like the chemical compounds. Just like some letters do not combine to
make words, some elements will not react to form compounds
Just like when letters combine to form words, those words take on new meanings….compounds are
exactly the same, they take on properties different from the properties of the elements that make them
up. Think about water: Hydrogen (Element - flammable gas) + Oxygen (Element - flammable gas)
react to form Water (a stable, non-flammable liquid)
Atomic Structure
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
What subatomic particles are in the nucleus of the atom and what is the charge of the nucleus?
Answer: Protons and neutrons so the charge of the nucleus is positive
The atom is composed mostly of empty space.
Where is most of the mass of the atom located? In the nucleus
How many electrons can exist in the first shell? The second? 2, 8, 8,18
Which two subatomic particles have approximately the same mass?
Answer: Neutrons and protons
Atoms with the same number of protons but different numbers of neutrons are called isotopes.
Periodic Table
Elements in the periodic table are arranged by atomic number OR the number of protons.
An elements properties can be predicted from its location in the periodic table.
The atomic number of an element is equal to the number of protons.
How can you find the number of neutrons in an atom? Atomic mass – atomic #
What makes one element different from another?
Using the Periodic Table
Draw a Bohr model of the element Chlorine, Cl.
2. Draw Bohr models of Carbon isotopes with atomic masses of 11, 12, and 13amu.
Chemical Reactions
Think about the chemical reaction: Mg + HCl => MgCl2 + H2
Can you identify the REACTANTS of this chemical reaction?
Can you identify the PRODUCTS of this chemical reaction?
Think about the chemical reaction: H2 + O2 => H2O
(We did this reaction when we lit the gas formed in the Mg + HCl reaction)
What TYPE of bond is water (IONIC or COVALENT)?
Explain the difference between these two types of bonds … you need to talk about the VALENCE
ELECTRONS
Is it likely for two metals (Sodium and Magnesium for example) to have a chemical reaction? Explain why or
why not in terms of the VALENCE ELECTRONS of each of their atoms.
Extra Questions
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.
Atomic number = # of protons
Atomic Mass = protons + neutrons
If an atom has 43 electrons, 56 neutrons, & 43 protons, what is the approximate atomic mass? What is the
element?
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.
ATOMS Practice TEST – STUDY GUIDE
Make sure you can answer the questions below…
Structure of the Atom
 Atomic Structure Worksheet (skim over)
1. The overall charge of an atom is ____________ if the number of _________ and
_____________ are the same.
Bill Nye Video
In the nucleus there are two particles the _____________ and the_________.
Moving around the nucleus are _______________.
Everything that is made of atoms is mostly ______________________.
What makes one atom different from another is the number of __________ in the
nucleus of the atom.
5. The atomic number is the number of ___________.
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Structure of the Atom Notes
1. Protons are found in the _________ and have a ________ charge.
2. Neutrons are found in the _________ and have __________ charge
3. Electrons are found in _________________ and have a _______ charge.
4. The nucleus is _______% of the mass of the atom. Protons and neutrons have about the _______
mass which is 1 ______. The electrons are ________ the mass of a proton or neutron.
5. What is the atomic number of Cl? How many protons?_____ Neutrons?____
6. The Atomic Number is __________________________________.
7. The Mass Number is ____________________________________.
8. Atomic Mass is _________________________________________ _________________.
9. An isotope is _______________________________________________ ___________________.
10. An ion is ___________________________________. An atom is a _________ ion if the number of
protons is greater than the number of electrons. It is a _____________ion if the number of protons is
less than the number of electrons.
1. Isotopes – know definition of isotope
2. The atomic mass is not a whole number because it is based on an _________ of all the isotopes of an
element.
Atomic Models
 Bohr Atomic Models (be able to draw a model of an atom by using the periodic chart)
1. The _________________ tells you the # of protons in the nucleus.
2. To find the number of neutrons you subtract the atomic number from the __________________.
3. _____ electrons fill the first energy level, _______ fill the 2nd energy level and ________ fill the 3rd
energy level if it is not the last level. The last level is filled with ________electrons.
4. Valence electrons are ______________________________________.
5. Valence electrons determine _________________________________.
6. Noble Gases do not react with other elements because _____________
____________________________.
7. Sodium wants to bond with chlorine because it has only ____ valence electron. It wants to _____ that
electron to Chlorine. Chlorine wants to take that electron because it has ____ valence electrons and so
only needs ____ more electron to have a filled outer level.
Chemical Reactions
Explain why metals (such as Sodium) react with non-metals (such as Chlorine) and form IONIC bonds.
Certain nonmetals (such as Hydrogen) usually form COVALENT bonds with other nonmetals (such as
Oxygen). Why does this happen – what do these atoms do so that all atoms are ‘happy’?