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57 Cards in this Set

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Anything that takes up space or has mass.
Vocab, chapter 2.1
A substance that can't be broken down to other substances by chemical reactions.

-92 elements occure in nature.
Vocab, chapter 2.1
A substance consisting of two or more different elements combined in a fixed ratio.

-A compound has char's different from those of its elements
Vocab, chapter 2.1

Ex: Table Salt
Trace Elements
Elements required by an organism in only minute quantities.
Vocab, Chapter 2.1

Ex: Iodine
What four elements make up 96% of living matter?
Carbon (C), Oxygen (O), Hydrogen (H), & Nitrogen (N).
Chapter 2.1 CCQ

Hint: These 4 elements are most abundant in the food you ate yesterday.
Why is table salt a compound, while the oxygen we breathe is not?
Table salt consists of two elements, whereas oxygen consists of only one.
Chapter 2.1 CCQ

Hint: How many elements are found in each?
The smallest unit of matter that still retains the properties of an element.
Vocab, chapter 2.2
Atomic Nucleus
An atom's central core, containing protons and neutrons.
Vocab, chapter 2.2

Hint: Different from the nucleus of a cell.
A subatomic particle with a single positive charge, found in the nucleus of an atom.
Vocab, chapter 2.2
A subatomic particle with a single negative charge.

One or more electrons move around the nucleus of an atom.
Vocab, chapter 2.2
An electrically neutral particle, found in the nucleus of an atom.
Vocab, chapter 2.2
A unit of measurement used for describing the mass of atoms and subatomic particles.

Protons and Neutrons both have a mass of one dalton. Electrons are so little that they are irrelevant.
Vocab, chapter 2.2

Hint: Same as the AMU (atomic mass unit)
Atomic Number
Number of protons in the nucleus of an atom.

In an electrically neutral atom, this will also tell you the number of electrons an atom has.
Vocab, chapter 2.2

Hint: Written as a subscript to the left of each element, such as ₂HE
Mass Number
Sum of protons plus neutrons in the nucleus of an atom.

You can find the number of neutrons by subtracting the Atomic Number from the Mass Number.
Vocab, chapter 2.2

Hint: Written as a superscript to the left of each element, such as ⁴HE
Atomic Mass
The total mass of an atom, in Daltons.
Vocab, chapter 2.2

Hint: The mass number is an *approximation* of this.
One of several atomic forms of an element, each containing a different number of neutrons and thus differing in atomic mass.

Isotopes of an element behave identically in chemical reactions.
Vocab, chapter 2.2
Stable Isotope
An isotope whose nucleus does not have a tendency to lose particles.
Vocab, chapter 2.2
Radioactive Isotope
An unstable isotope. The nucleus of a radioactive isotope decays spontaneously, giving off particles and energy.

If the decay leads to a loss of protons, it will change to a different element.
Vocab, chapter 2.2

Hint: Opposite of a stable isotope.
The capacity to cause change.
Vocab, chapter 2.2
Potential Energy
The energy that matter possesses because of its location or structure.
Vocab, chapter 2.2

Hint: The higher off the ground an object is, the more PE it has.
Energy Levels
The different states of potential energy that electrons have in an atom.

An electron's energy level is correlated with its average distance from the nucleus. These average distances are represented symbolically by electron shells.
Vocab, chapter 2.2

Hint: In relation to an atom.
Electron Shells
Symbolic representation of the average distance from the nucleus an electron is at.

First shell = closest to the nucleus, and least potential energy.
Vocab, chapter 2.2
Can an electron change the Electron Shell it occupies? How?
An electron can change the shell it occupies by absorbing or losing an amount of energy equal to the difference in potential energy between its position in the old shell and that in the new shell.
Chapter 2.2

Hint: Yes, it can.
What happens when an electron absorbs energy? When it loses it?
When an electron absorbs energy, it moves to a shell farther out from the nucleus.

When an electron loses energy, it falls back to a shell closer to the nucleus and the lost energy creates heat.
Chapter 2.2

Hint: Involves electron shells.
What determines the chemical behavior of an atom?
Its electron configuration, mainly its number of valence electrons.
Chapter 2.2
Valence Shell
The outermost electron shell of an atom.
Vocab, chapter 2.2
Valence Electrons
The electrons housed in the outermost electron shell of an atom.
Vocab, chapter 2.2
What is true of atoms with the same number of electrons in their valence shells?
They exhibit similar chemical behavior.
Chapter 2.2
What is true of an atom with a completed valence shell?
It is chemically unreactive, or "Inert".
Chapter 2.2
The 3D space where an electron spends 90% of its time.
Vocab, chaper 2.2
How many electrons can occupy a single orbital?
No more than two.
Chapter 2.2
What causes the reactivity of an atom?
The presence of unpaired electrons in one or more orbitals of their valence shells.
Chapter 2.2
A lithium atom has 3 protons and 4 neutrons. What is its atomic mass in Daltons?
Seven (3 protons plus 4 neutrons).
Chapter 2.2, Concept Check Question
A nitrogen atom has 7 protons, and the most common isotope of nitrogen has 7 neutrons. A radioactive isotope of nitrogen has 8 neutrons. What is the atomic number and mass of this radioactive nitrogen? Write as a chemical symbol with a subscript and superscript.
Atomic Number = 7
Atomic Mass = 15
Chapter 2.2, Concept Check Question
In an electron-shell diagram of phosphorus, in which shell do electrons have the most potential energy? The least?
The further away from the nucleus an electron is, the more potential energy it has.
Chapter 2.2, Concept Check Questions
Chemical Bonds
An attraction between two atoms, resulting from a sharing of valence electrons or the presence of opposite charges on the atoms. The bonded atoms gain complete valence electron shells.
Vocab, chapter 2.3
Covalent Bond
The sharing of a pair of valence electrons by two atoms.
Vocab, chapter 2.3
Two or more atoms held together by covalent bonds.
Vocab, chapter 2.3
Single Bond
A pair of shared electrons.
Vocab, chapter 2.3

Ex: H-H
Structural Formula
A type of molecular notation in which the constituent atoms are joined by lines representing covalent bonds.
Vocab, chapter 2.3

Ex: H-H or H=H
Molecular Formula
A type of molecular notation indicating only the quantity of the constituent atoms.
Vocab, chapter 2.3

Ex: H₂
Double Bond
Two pairs of shared electrons.
Vocab, chapter 2.3

Ex: H=H
(An Atom's) Valence
The bonding capacity of an atom, usually equal to the number of unpaired electrons in the atom's valence shell.
Vocab, chapter 2.3
The attraction of a particular kind of atom for the electrons of a covalent bond.

The more electronegative an atom is, the stronger it pulls shared electrons toward itself.
Vocab, chapter 2.3
Nonpolar Covalent Bond
Two atoms are equally electronegative, and electrons are shared equally between them.
Vocab, chapter 2.3

Hint: The opposite of water.
Polar Covalent Bond
One atom is more electronegative than the other, and so the electrons of the bond are not shared equally.
Vocab, chapter 2.3

Hint: Water
An atom that has gained or lost electrons, thus acquiring a charge.
Vocab, chapter 2.3
A positively charged ion.
Vocab, chapter 2.3

Hint: It's lost electrons
A negatively charged ion.
Vocab, chapter 2.3

Hint: It's gained electrons.
Ionic Bond
A chemical bond resulting from the attraction between oppositely charged ions.
Vocab, chapter 2.3
Ionic Compounds (Salts)
A compound resulting from the formation of an ionic bond.
Vocab, chapter 2.3
Hydrogen Bonds
Form when a hydrogen atom covalently bonds to one electronegative atom that is also attracted to another electronegative atom.
Vocab, chapter 2.3
Van der Waals Interactions
Weak attractions between molecules or parts of molecules that are brought about by localized charge fluctuations.
Vocab, chapter 2.3
A molecule's shape is determined by what?
The positions of the atoms' orbitals.
Chapter 2.3
Why is molecular shape crucial in biology?
Because it determines how biological molecules recognize and respond to one another with specificity.

Only molecules with complementary shapes are able to bind to each other by weak bonds.
Chapter 2.3
Why does the following structure fail to make sense chemically?

Because each carbon has only three covalent bonds instead of the required four.
Chapter 2.3 Concept Check Question
Explain what holds together the atoms in a crystal of magnesium chloride?
The attractions between oppositely charged ions form ionic bonds.
Chapter 2.3 Concept Check Question