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25 Cards in this Set

  • Front
  • Back
What is matter? Give examples.
- anything that takes up space and has mass
- eg.: rock, wood, air
What is an element? Give examples.
- a pure substance that cannot be broken down by chemical means
- eg.: oxygen, helium, hydrogen
What are the 4 main elements in our bodies?
1. oxygen
2. carbon
3. nitrogen
4. hydrogen
What is a compound? Give examples.
- a substance made up of 2 or more elements that are chemically combined in a fixed ratio
- eg.: water, carbon dioxide
What is an atom? Give examples.
- smallest possible particle of an element
- carbon atom is smallest possible 'piece' of carbon
What are the 3 parts of an atom?
What charge does each have?
1. proton -> positive
2. neutron -> neutral
3. electron -> negative
What is the structure of an atom? What is in the center (NUCLEUS) and what is on the outside?
The nucleus is made up of protons and neutrons, while the outside is made of electrons.
What is the ATOMIC NUMBER?
It is equal to the number of protons.
An atom has an atomic number of 6, how many protons does it have?
If the atom is neutral, how many electrons does it have?
The same number as protons.
What is the key to determining how an atom will react?
By the organization of the atom's outer most electrons.
How many electrons are found in the first energy level of an atom?
2 electrons
How many electrons are found in the second, third, fourth, etc. energy levels?
8 electrons
If an atom like Carbon, does not have all of its electrons in the outer most energy level, is it reactive?
Yes, it is reactive.
If an atom like Helium has all of its electrons in the outer most shell, is it reactive?
No, it is not reactive - no space to add more electrons.
What is an ionic bond? Examples?
An ionic bond is formed between to oppositely charged ions. It occurs after one atom gives an electron to another atom.

NaCl (table salt)
What is an ion?
It is an electrically charged particle, formed by gaining or losing an electron.
What is the best example of an ionic bond?
NaCl (table salt)

Na gave an electron to Cl.
Na -> Na+
Cl -> Cl-
If an atom gains an electron, what charge does it have (positive or negative)?
It becomes a negative ion.
If an atom loses an electron, what charge does it have (positive or negative)?
It becomes a positive ion.
What is a covalent bond? Example?
It is formed when 2 atoms share electrons. The bond between H and O in water.
Suppose an atom can fit 8 electrons in its outer most shell but it only has 4 electrons, how many bonds can it form with Hydrogen?
4 bonds

CH4 (methane)
What is a molecule? Example?
A molecule is the smallest piece of a compound. It is made of 2 or more atoms held together by covalent bonds. A water molecule is a good example.
What is the difference between a chemical formula and a structural formula?
Chemical formula: indicates the ratio of elements in the compound.

Structural formula: indicates the way in which the elements are linked.
What is a chemical reaction?
The process by which one or more new substances are formed by rearranging existing substances by breaking and making bonds.