Campbell Biology Chapt 2

Front 1

Matter

Back 1

Consist of chemical elements in pure form and in combinations called compounds

Organisms are composed of matter

Anything that takes up space

Front 2

Element

Back 2

A substance that cannot be broken down to other substances by chemical reactions

Front 3

Compound

Back 3

Sunstance consisting of two or more elements in a fixed ratio

Sodium + chlorine= sodium chloride aka salt

Front 4

Essential elements

Back 4

About 20-20% of the 92 elements

Required for life

Carbon, hydrogen, oxygen, and nitrogen make up 96% of matter

Front 5

Trace elements

Back 5

Needed by an organism in minute quantities making up about 4 %

Some like iron are needed by all forms, others by just some forms of life

Still an essential element

Front 6

Atom

Back 6

Smallest unit of matter that retains the properties of an element

Composed of subatomic particles

Front 7

Subatomic particles

Back 7

Neutrons-neutral

Protrons-positive charge

Electrons-negative charge

Front 8

Atomic nucleus

Back 8

Made up ofprotons and neutrons

Electrons form cloud of negative charge around the nucleus (2 electrons)

Neutron and protrons mass are almost identical and measured in daltons

Front 9

Dalton

Back 9

Mass of 1.7x10-24

Front 10

What make an element an element?

Back 10

The number of protons

Or the atomic number

Front 11

Atomic nunber

Back 11

Number of protons in its nucleus

Front 12

Mass number

Back 12

Sum of protons plus neutrons in the nucleus

Front 13

Atomic mass

Back 13

Atoms total mass

Front 14

Isotopes

Back 14

Same number of protons but have different neutrons

Carbon has different isotopes

Front 15

Radioactive isotopes

Back 15

Decay spontaneously giving off particles and energy

Aka transmute and end up with a different number of protons which changes the element

Front 16

Radioactive tracers

Back 16

Can be used to track atoms through metabolism

Used a diagnostics tools in medicine

Can be used in combination with imaging instruments

Front 17

Energy

Back 17

The capacity to cause change

Front 18

Potential energy

Back 18

Energy that matter has bc of its location or structure

Gravity around earth

Electrons of an atom differ in their amts of potential energy due to their distance from the atomic nucleus

The farther the electron is, the more potential energy it has

Front 19

Electron shells

Back 19

An electrons state of potential energy aka its potential energy

They can jump to other shells but it takes more energy and you can release energy as you move them in

First: has lowest energy, most stable

Second: higher

Third: highest

Front 20

Electron distribution

Back 20

If you have two protons, then you have two electrons which fills first outer shell.

Then you can fill next shell and so on.

The first shell can only have two electrons

The shells after hold up to 8 electrons

Front 21

Valence shell

Back 21

The outer shell

Valence electrons are there

Elements that have similar number of electrons in their outer shell, behave in a chemically similar way (ie: hydrogen, lithium, sodium all have one electron I their outer shell)

Front 22

Noble gases and chemically inert

Back 22

All elements want to fill their valence shell

Chemicals that are full do not react much chemically because they are “satisfied”

Neon, argon examples

Front 23

Electron orbital

Back 23

A 3 dimensional space where electron is found 90% of the time

Each shell consists of a specific number of orbitals

These shapes hold them in pairs and allow them to be as far as part as they can be

Influence the shape of a molecule

Front 24

Chemical bonds

Back 24

Atoms with incomplete valence shells can share or transfer valence electrons with certain other atoms

When this happens, atoms usually stay close together, held by attraction

Can vary in strength

Varieties of types of chemical bonds

Front 25

Covalent bonding

Back 25

Sharing of valence electrons between two atoms

Strongest bond is when all valence shell is full

A molecule consists of 2 or more atoms sharing a covalent bond

Front 26

Single bond

Back 26

Sharing of one pair of valence electrons

Front 27

Double covalent bond

Back 27

Sharing 2 pairs of valence electrons

Front 28

Atom’s valence

Back 28

Binding capacity

How many electrons that are not paired (O has 6 valence electrons, two are not paired so oxygen’s valence is 2)

Front 29

Van der waal interaction

Back 29

Electrons are not evenly distributed and may accumulate by chance in one molecule

Temporary dipole

Geicko foot

Front 30

Electronegativity

Back 30

An atoms attraction for the electrons in a covalent bond

Atoms in a molecule attract electrons to varying degrees

The more protons and the less shells=more electronegativity

Electronegativity increases as you go left to right on the periodic table because more protons are added to the atomic nucleus

Adding more shells makes atoms less electronegativity

Oxygen

Front 31

Nonpolar covalent bond

Back 31

Atoms share the electron equally

Front 32

Polar covalent bond

Back 32

One atom is more electronegative and they do not share equally

Causes partial positive or partial negative charge for each atom or molecule

Tends to be colder

Front 33

Ionic bond

Back 33

An attraction btw a cation and an anion

Due to strong electronegativity, some atoms can strip electrons from bonding partners

This allows for some atoms to lose an electron which can eliminate their valence shell and now they are “full”

Front 34

Cation

Back 34

A positively charged ion

Front 35

ionic compounds

Back 35

Compounds formed by ionic bonds compounds

Highly charged

Aka salt

Different salts have different ratios

Often found in nature as crystals

Front 36

ionic compounds

Back 36

Compounds formed by ionic bonds compounds

Aka salt

Different salts have different ratios

Often found in nature as crystals

Front 37

Hydrogen bond

Back 37

When hydrogen covalently bonded to an electronegative is attracted to another

Two molecules bonded

Oxygen and nitrogen are most common in living cells

Your dna is held together by hydrogen bonds

Front 38

Van der waal interaction

Back 38

Electrons are not evenly distributed and may accumulate by chance in one molecule

Temporary dipole

Partial charge creates a weak charge charge interaction

Geicko foot

Front 39

Molecular shape and function

Back 39

A molecules size and shape are key to function

Shape Determined by position of its atoms orbitals

In covalent bonds, the s and p orbitals hybridize creating specific molecular shapes

Front 40

Chemical reactions

Back 40

Make and break chemical bonds

All reactions are reversible: products became reactants

Front 41

Reactants

Back 41

Starting molecules of a chemical reaction

Front 42

Products

Back 42

The final molecules of the chemical reaction

Front 43

Chemical equilibrium

Back 43

Happens when the reverse and forward reactions happen at the same rate

Does not mean the number of molecules are equal

The relative concentrations of reactants and products do not change