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AP Bio Chapter 2
Elements, compounds, and atoms, Chemical bonds
39
Biology
10th Grade
09/13/2010

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Term
What is the difference between elements and compounds?
Definition
Elements cannot be broken down into other substances and consist of one element. Compounds can be broken down into other substances and consist of two or more different elements.
Term
Is O2 an element or a compound? Is NaCl an element or a compound?
Definition
O2 is an element. NaCl is a compound.
Term
What four elements make up 96% of living matter?
Definition
CHON.
(carbon, hydrogen, nitrogen, oxygen)
Term
What are some elements that make up 4% of living matter?
Definition
PSCaK
Phosphorus, sulfur, calcium, potassium
Term
What are trace elements and what are some examples of them?
Definition
Trace elements are elements that an organism needs in very small quantities. An example of a trace element is iodine. Without it people get goiter.
Term
What is the smallest unit of matter the still retains the properties of an element?
Definition
An atom
Term
What are the three main subatomic particles and what are their charges?
Definition
Proton- positive
Neutron- neutral
electrons- negative
Term
What is found in the nucleus? What is found outside the nucleus in the cloud?
Definition
Protons and neutrons are found in the nucleus. Electrons moving at nearly the speed of light form a cloud around the nucleus.
Term
The mass of an electron is only _____ as much as the mass of a proton or neutron.
Definition
1/2000
Term
What unit of measurement is used for atoms and subatomic particles?
Definition
dalton, Atomic mass unit, amu
Term

[image]

What is the atomic number?

What is the mass number?

Definition

Atomic number-30

Mass number-65

Term

[image]

How many protons, electrons, and neutrons does this element have?

(exclude the 2+)

Definition

Protons-30

Electrons-30

Neutrons-35

Term
What are isotopes?
Definition
Atoms of the same element that have different amounts of neutrons.
Term
What is a radioactive isotope and how are they used in science?
Definition
The nucleus of a radioactive isotope decays spontaneously, giving off particles and energy. It is used in radioactive dating(C-14), monitoring biological processes, and diagnosing illness.
Term
Where is most of the mass of an atom?
Are atoms really mostly empty space?
Definition
Most of the mass of an atom is in the nucleus. Atoms are mostly empty space.
Term
Which has more potential energy: a penny on the ground or a penny on top of a building? Why?
Definition
The penny on top of the building has more potential energy because of its altitude.
Term
Which electrons have more potential energy: the electrons closer to the nucleus of the electrons farther away from the nucleus?
Definition
The ones farther away from the nucleus.
Term
How does an electron jump between energy levels? Can an electron exist(for a long time) between its energy levels?
Definition
An electron can jump between energy levels by absorbing or losing energy. An electron cannot exist between its energy levels.
Term
How many electrons can be in the first electron shell? The second?
Definition
First- 2
Second-8
Term
How many orbitals are in the first electron shell? In the second? What are the shells called?
Definition
First- one orbital, 1s
Second- four orbitals, 2s, 2py, 2pz, 2px
Term
What is an orbital and how many electrons can be in one orbital?
Definition
An orbital is a 3D space where an electron is found 90% of the time. Up to two electrons can be in each orbital.
Term
What is the difference between a covalent bond and an ionic bond?
Definition
In a covalent bond atoms share electrons. In an ionic bond, one atom loses electron(s)and another atom gains electron(s).
Term
When two oxygen atoms share two pairs of electrons, is that a double or single bond?
Definition
Double
Term
Covalent is to molecule as ionic is to ____?
Definition
Salt
Term
How does electronegativity affect the polarity of molecules?
Definition
If two covalently bonded atoms are equally electronegative, then they have a nonpolar bond. If the atoms have different levels of electronegativity, then the molecule is polar.
Term
Is water a nonpolar or polar bond?
Hydrogen has low electronegativity and oxygen has a very high electronegativity.
Definition
Polar bond.
Term
What is a positive ion called? A negative ion?
Definition
Positive- cation
Negative- anion
Term
Can the term ion be applied to whole molecules, or only single atoms?
Definition
It can be used with molecules that are electrically charged, such as ammonium.
Term
How can weak bonds be an advantage in living organisms?
Definition
Two molecules can come together, respond to one another in some way and separate, without the use of too much energy.
Term
When does a hydrogen bond form?
Definition
When a hydrogen covalently bonded to one electronegative atom is attracted to another electronegative atom. For example, water.
Term
Why do Van der Waals interaction occur?
Definition
They occur because electrons are always in constant motion, so one part of a molecule may be a little positive or negative. This enables molecules to stick to each other. It is also why when people pour water out of a cup, the water runs down the side of the cup instead of into the container it was suppose to go into.
Term
When can Van der Waals interactions occur?
Definition
When atoms and molecules are very close to each other.
Term
Why is the precise shape of a molecule important?
Definition
The shape of a molecule determines how it will be recognized and how it will respond with other molecules.
Term
What is the angle at which the hydrogens in water are bent?
Definition
104.5
Term
In a chemical reaction, the starting materials are called_____ and the end materials are called______.
Definition
Reactants, products.
Term
True or false.
Most reactions are reversible.
Definition
True
Term
True or false. In chemical equilibrium, the reactants and products are equal in concentration.
Definition
False. The concentrations are not necessarily equal. They have only stabilized at a particular ratio.
Term
What happens when chemical equilibrium is reached?
Definition
The reactions offset each other. Aka, reactants and products are being made at the same rate.
Term
What is the chemical equation for photosynthesis? (just for fun)
Definition
6CO2 + 6H2O ==> C6H12O6 + 6O2
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