Biology
Name : __________________
Date : __________________
Period : _________________
2-1
The Nature of Matter
Atoms

The study of _________________ begins with the basic unit of __________, the
___________.

The Greek philosopher ___________________ called the smallest fragment of matter the
_____________, from the Greek word _______________.
Atoms

Placed side by side, __________ million atoms would make a row only about _____
centimeter long.

Atoms contain _________________ ___________________ that are even smaller.
Atoms

What _____________ subatomic particles make up ____________?

The subatomic particles that make up atoms are
a.
b.
c.
Atoms

The subatomic particles in a ________________ atom.
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Atoms

___________________ and ___________________ have about the same mass.

__________________ are _______________________ charged particles (+).

__________________ carry _________ charge.

Strong forces ___________ protons and neutrons _____________ to form the
___________________, which is at the center of the atom.
Atoms

The _____________________ is a _______________ charged particle (−) with 1/1840 the
mass of a proton.

Electrons are in ___________________ motion in the space ___________________ the
nucleus.
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Atoms

___________________ are _________________ to the __________________ charged
____________________ but remain outside the nucleus because of the
________________
of their _________________.
Atoms

Because ____________ have ______________ numbers of electrons
and _______________, and because these subatomic _______________
have equal but ________________ ________________, atoms are _______________.
Elements and Isotopes

A chemical ____________________ is a pure substance that consists entirely of
_____________ type of atom.

Elements are represented by a ___________- or __________-letter symbol.
_____ stands for ____________________.
_____ stands for ___________________.
Elements and Isotopes

The number of _____________________ in an atom of an _____________________ is the
element's _________________ ________________________.

___________________ has ______ protons, so its atomic _______________ is 6.

More than ____________ elements are known, but only about _________ dozen are
commonly found in ___________________ organisms.
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Elements and Isotopes
Isotopes

Atoms of the _______________ element that _____________ in the number of
___________________ they contain are known as _______________________.

The __________ of the __________________ and ________________ in the nucleus of an
atom is called its ___________ number or _____________________ Mass.
Elements and Isotopes

_________________ are identified by their Atomic ___________ numbers.

For example, carbon has ____________ isotopes—carbon-___, carbon-___, and carbon-___.
Each ____________ has a different number of ______________.
Elements and Isotopes
How are all of the ______________________ of an element similar?

Because they have the ___________ number of __________________, all
_________________ of an element have the same _____________________ properties.
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Elements and Isotopes
Isotopes of Carbon
6 electrons
6 protons
8 neutrons
Elements and Isotopes
Radioactive Isotopes

Some ________________ are _____________________, meaning that their nuclei are
_________________ and break down at a __________________ rate over time.

Although the radiation these ___________________ give off can be dangerous, they have
important ______________________ and _______________________ uses.
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Elements and Isotopes
Radioactive isotopes can be used:

to determine the ________ of _______________ and fossils.

to treat ____________________.

to kill ____________________ that cause food to __________________.

as labels or “___________________” to follow the ____________________ of substances
within an _______________________.
Chemical Compounds

In nature, most ________________ are found combined with other elements in
_________________________.

A chemical ___________________ is a substance formed by the chemical combination of
_________ or more ___________ in definite proportions.

The _____________________ and ___________________ properties of a compound are
different from the _______________________ from which it is formed.
Chemical Compounds

Scientists show the _____________________ of compounds by a kind of shorthand known as
a ____________________ ____________________.

Water, _________, contains two atoms of ___________________ for each atom of
_____________________.

The formula for table salt, ____________, indicates that _______________ and
_______________ combine in a ___ : ___ ratio.
Chemical Bonds
What are the two main types of ________________ ________________?
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Chemical Bonds

The atoms in _____________________ are held together by chemical ________________.

______ formation involves the ____________ that surround each ____________ nucleus.

The __________________ that are available to form ____________ are called
_______________ electrons.
Chemical Bonds

The main types of chemical bonds are:
a.
b.
Chemical Bonds
Ionic Bonds

An __________ ___________ is formed when one or more _________________ are
transferred from one ______________ to another.

An _____________ that loses _________________ has a ______________ charge.

An atom that _____________ electrons has a ________________ charge.

These __________________ and ________________ charged atoms are known as
____________.
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Chemical Bonds
Chemical Bonds
Covalent Bonds

Sometimes ________________ are _______________ by atoms instead of being
___________________.

_________________ electrons means that the moving _______________ actually travel in the
__________________ of both atoms.
Chemical Bonds

A ____________________ bond forms when _________________ are __________________
between atoms.

When the atoms ______________ two ________________, the bond is called a
_____________ covalent bond.

When atoms share _____________ electrons it is called a ________________ bond.

When atoms share _______________ electrons it is called a ___________________ bond.
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Chemical Bonds

The _______________ that results when atoms are joined ____________________ by
covalent bonds is called a ___________________.

A _____________________ is the smallest unit of most __________________.
Chemical Bonds

In a ______________ molecule, each ____________________ atom forms a single
_________________ bond with the ______________________ atom.
Chemical Bonds
Van der Waals Forces

When molecules are _______________ together, a slight ______________________ can
develop between the ___________________________ charged ____________________ of
nearby molecules.
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
Chemists call such intermolecular forces of attraction ______ ______ _________
______________, after the scientist who discovered them.
Chemical Bonds

Although van der Waals forces are ________ as _____________ as ____________ bonds or
_________________ bonds, they can hold _______________ together, especially when the
molecules are __________________.
Chemical Bonds

For example, van der Waals forces form between the _________________ on the surface of a
_______________ foot and the molecules on the ___________________ of the wall.

The combined _________________ of all the van der Waals ___________________ allows
the gecko to grip the wall.
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QUIZ
2-1
1. The particles that move around the nucleus of an atom are called
a. neutrons.
b. protons.
c.
electrons.
d. isotopes.
2-1
2. The atomic number of a carbon atom is 6. How many neutrons does the isotope carbon-14 have?
a. 6
b. 8
c. 12
d. 14
2-1
3.
Which of the following statements about the three isotopes of carbon is true?
a. They are all radioactive.
b. They have different numbers of electrons.
c.
They have the same chemical properties but differ in atomic mass.
d. They have the same number of protons and neutrons.
2-1
4. A chemical compound consists of
a. electrons mixed with neutrons.
b. two or more elements combined in a definite proportion.
c.
two or more elements combined in any proportion.
d. at least three elements combined by ionic or covalent bonds.
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2-1
5. Van der Waals forces are the result of
a. unequal sharing of electrons.
b. ionic bonds.
c.
the bonding of different isotopes.
d. the chemical combination of sodium and chlorine.
END OF SECTION
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