Chapter 2/3 - Molecules Flashcards
Any substance in the universe that has mass and occupies space
Matter
Small particles that make up matter
Atoms
Tunneling microscopy
Technology used to locate atoms
What located at the center of an atom?
Nucleus
What subatomic particles form the nucleus?
Protons and neutrons
What subatomic particles surround an atom?
Electrons
Electrons are found in
Orbitals
Orbitals surround the
Nucleus of an atom
Region within an atom where the electron will most likely be located
Orbital
How many electrons can an orbital contain
2
Atomic theory
- Every atom contains electrons
2. Protons and neutrons are at the core of an atom
What charge does a proton have?
Positive
What charge does an electron have?
Negative
What charge does a neutron have?
No charge
Any substance that cannot be broken down into any other substances by ordinary chemical means
Element
Atomic number is equal to the number of
Protons
True or False
Atoms with the same atomic number belong to the same element
True
True or False
Different atoms have the same number of protons
False
Different atoms have a different number of protons
Pure substance that contains one atom
Element
True or false
Our body is made up of elements
True
Oxygen has eight protons so that atomic mass is
8
The atomic mass is equal to
Protons plus neutrons
Which subatomic particles contribute to mass
Protons and neutrons
True or false
Electrons contribute to mass and are heavier than protons and neutrons
False
Electrons do not contribute to mass and are not heavier than protons or neutrons
An atom is generally neutrally charged when
Where is an equal number of protons and electrons
Keeps electrons in their orbitals but opposite charge attraction
Protons
Can be gained or lost, turning into an ion
Electrons
Ion
When the number of electrons does not equal the number of protons
Name two types of ions
Cation
Anion
Cation
- Positive charge ion
2. Contains more protons than electrons
Anion
- Negative charge ion
2. Less protons than electrons
True or false
Typically, an atom has one electron for each proton and is thus electrically neutral
True
The chemical behavior of an atom is due to the number and configuration of
Electrons
Positive charges in the nucleus of an atoms are neutralized by
Negatively charged electrons
Isotope
Different form of the same element that possesses the same number of protons but different number of neutrons
The mass of atoms and subatomic particles is measured in units called
Daltons
A proton weighs approximately
1.007 Dalton
A neutron weighs approximately
1.009 dalton
Electrons weigh
1/1840 of a dalton, so they contribute almost nothing to the overall mass of an atom
Na , Cl
Na+ —> Cl-
Which element is a cation/ which is an anion? Explain.
Na+ is the cation. It shared/lost its electron to Cl-. Giving it more protons than electrons. Thus, the positive charge.
Cl- is the anion. A gain an electron from an Na+. Giving it more electrons than protons. Thus, the negative charge.
Hydrogen has 1 proton, 0 neutrons.
Deuterium has 1 proton, 2 neutrons.
Tritium has 1 proton, 3 neutrons.
What is being described?
An isotope.
Same element possessing the same number of protons but different number of neutrons.
Radioactive isotope
- Unstable isotopes that will break down into an atom with a lower number of neutrons and or atomic number
- Undergoes radioactive decay
- release energy
Radioactive decay
Unstable isotope that decays to an element with a lower atomic number
True or False
Some radioactive isotopes are more unstable than others
True
The decay time for a radioactive isotope is expressed as
Half life
The time it takes for 1/2 of the atom in a sample to decay
Half life
100%. Vs. 50% Ex: 12C --- > Half Life = 7C
How are fossils dated?
Through radioactive decay
Emits large quantities of energy that are harmful to living cells
Radioactive decay
Determines the chemical behavior of an atom
Electrons
What shapes are ORBITALS known to have
Spherical
Dumbbell shaped
Describe the 1s orbital
- Closest to the nucleus of an atom
2. Lowest energy level
Describe 2s, 2p orbital
- Further away from the nucleus of an atom
- Second lowest energy level
- 2s = 2 electrons
- 2p = 3 orbitals
**Max of eight electrons
Name all energy levels alphabetically from lowest to highest
- K —-> lowest (1s)
- L (2s;2p)
- M
- N —-> highest
How can you move electrons away from the nucleus?
Add energy
How can you move electrons closer to the nucleus?
Release energy
When energy is released electrons move
Closer to the nucleus —–> because energy at lower orbitals contain less energy than orbitals further away from the nucleus
When energy is absorbed electrons move
Further away from the nucleus, or the outer orbital
What energy level is closest to the nucleus and which is furthest?
Close , K
Far , N
- How many electrons can the outer most energy level contain?
- Name two exceptions.
- 8
- He, H —-> Each contains a 1s orbital ONLY.
How can you increase the potential energy of an electron
Input energy
The amount of energy and electron possesses it is related to its distance from
The nucleus
Electrons that are the same distance from the nucleus have the same
Energy
Oxidation
Transfer/Loss of an electron by an atom or molecule, in metabolism
Usually associated with the gain of oxygen or loss of hydrogen
Reduction
Gain of electron
Redox Reaction
An atom or molecule becomes oxidized, while another is reduced in the same reaction
How many naturally occurring elements are there?
90
Each w different number of protons and a different arrangement of electrons
True or false
Elements have a repeating pattern of 6 elements
False
Elements have a repeating pattern of eight elements
Electrons in the outer most energy level are called
Valance electrons
Nonreactive/ Inert / “Happy”
Elements that contain all eight valance electrons in their outer most energy level
If an element contains all eight electrons in its outer most energy level can it bond with other elements
No because it is non-reactive, happy or inert
Elements that contain less than eight electrons are
Very reactive
Elements that contain seven electrons will try to
Fill up their outer most energy level
Elements that contain one electron will try to
Rid there outermost electron
What is it called when one element loses its electron to another element
Ionic bond
Octet rule
Atoms like to completely fill their outer energy levels
If helium has two valance electrons and nitrogen has four valance electrons, which element would be very reactive?
Helium is non-reactive due to its 1s orbital, therefore nitrogen would be very reactive
What 12 elements are found in living organisms?
C, H, O, N, P, S, Na, K, Ca, Mg, Fe, Cl
Which elements make up 96.3% of your bodyweight?
C, H, O, N
Compounds found in living organisms that contain carbon
Organic compounds
Carbon is found in
Sugars, fatty acids, and amino acids
What does the Periodic Table display
Elements according to atomic number and properties
K has 1 valence electron/Br has 7 valence electrons. Based on the octet rule which element will be oxidized and which will be reduced? Explain.
K will be oxidized. It is very reactive and will rid its 1 valence electron.
Br will be reduced. It also is very reactive and will gain an electron from K instead of getting rid of its 7 valence electrons.
True or false
All noble gases are non-reactive
True
Majority of molecules that make up your body
Organic compounds
A group of atoms held together by energy and a stable association is called a
Molecule
ELEMENT Na has lost an electron to ELEMENT Cl, what type of bond is this?
Ionic bond
When a molecule contains atoms of more than one element it is called
A compound
When to or more elements are joined
Chemical bond
How can an ionic bond or lattice be broken?
In the presence of water/ or present water/ H2O
***ex: Na+ , Cl-
Na+ and CL- are attracted to the opposite poles of water, this allows Na to retain its + charge and Cl to retain its - charge
What bond that forms a Crystal, Solid, or lattice?
Ionic bond
Covalent bond
When 2 atoms share a valance electron
Or
When 2 or more atoms share one or more pairs of electrons
Forms when atoms with opposite electrical charges (ions) attract
(+)Cation ^ Anion(-)
Ionic bonds
True or false
NaCl is common table salt
True
Lattice, solid, crystal
Are covalent bond stable? Explain.
Yes, covalent bond are stable.
- NO NET CHARGE, so neither atom loses or gains electrons
- SATISFIES OCTET RULE, shared electrons can orbit both atoms.
- HAS NO UNPAIRED ELECTRONS , free electrons shared between two atoms are now paired.
Do double bonds satisfy the octet rule?
Yes, by allowing to atoms to share two pairs of electrons
True or false
The strength of covalent bond depends on the number of shared electrons
True
Ex: Triple bond > double bond > single bond
In a covalent bond what does — represent?
The sharing of one electron pair
How many valence electrons does carbon have?
4
Carbon can form multiple covalent bonds because it has
Four valance electrons
Affinity for electrons
Electronegativity
Increases left to right across a row of the periodic table and decreases down the column
Electronegativity
Nonpolar covalent bond
- Affinity for electrons is the same, the electrons are equally shared.
- Equal electronegativity
**Neither element is pulling the electrons more than the other because equal electronegativity
** Same element
** different elements with a very similar electronegativity
Polar covalent bond
Unequal electronegativity
Electrons are not shared equally
Atoms differ greatly in electronegativity
Shared electrons are more likely to be closer to the atom with greater electronegativity and less likely to be near the atom of lower electronegativity
Electrically neutral
Contains regions of partial negative charge near the more electronegative atom
Polar covalent bonds
Contains regions of partial positive charge near the less electronegative atom
Polar covalent bond
Formation or breaking of chemical bonds
Chemical reaction
What are chemical reactions to dependent on?
- Temperature, which affects the speed of molecular movements
- Centration of products or reactants,
More reactant = more reaction
Less reactant = less reactant
- Catalysts
Speeds the rate of reactions
What protein catalyzes almost every chemical reaction in living systems
Enzymes
Consist of 2H covalently bonded to 10
Water
True or false
Water is not stable
False
Water is very stable
- Satisfies octet rule
- All electrons paired
- Carries no net electrical charge
Which has a higher electronegativity, oxygen or hydrogen?
Oxygen
Is a water molecule polar or nonpolar?
Polar
H2O carries two partial negative charges near
Oxygen
H2O carries to partial positive charges on
Each hydrogen
High polarity of water allows formation of
Hydrogen bonds
True or false
Hydrogen bonds organize most of the molecules in living systems
True
Bonds between partially negative O atoms and the partially positive H atoms of two water molecules form
Hydrogen bonds
Since water molecules attract each other they are
Cohesive
Because water molecules are attracted to other polar molecules they are
Adhesive
True or false
The polarity of water allows water molecules to be attracted to one another
True
Water is cohesive
What is responsible for water being a liquid and not a gas
Waters cohesion
True or false
The polarity of water allows it to be attracted to other polar molecules
True
Water is adhesive
Specific heat
The amount of heat needed to be absorbed or lost by 2g of a substance to raise or lower is the temperature by 1°C
How much energy do you need to put into a substance to raise or lower its temperature?
This question describes what.
Specific heat
Heat of vaporization
The amount of heat needed to change a liquid to a gas
How much heat do you need to put into change that substance from a liquid to a gas
The question is an example of what.
Heat of vaporization
Does water have a high specific heat
Yes
Due to its unique nature in forming hydrogen bonds
Partial + and Partial - allow water to form
Hydrogen bonds
How can a hydrogen bond be broken
By an abundance of thermal energy or heat
Does water take awhile to heat up?
Yes, because it has a high specific heat so you need a lot of heat to heat up water
Biological systems/living organisms are mostly composed of water which helps to maintain
Body temperature
Biological reaction
- Produces heat
- Transfers heat to surrounding water ( breaks a couple hydrogen bonds )
Overheating and biological systems is possible without the presence of
Water
Does water have a high heat of vaporization?
Yes.
As he is released from the body, any water to the surface of the body, he will break down does hydrogen bonds, water will evaporize to air.
Ex: Too hot—-> sweat
Do polar ions carry a charge?
Yes.
Anion / cation
Is a polar ion soluble in water?
Yes
True or false
Water is not attracted to polar ions
False
Water is attracted to polar ions
Water surrounds ions to form
Hydrogen bonds within a water molecule
Is water a solute, or solvent?
Solvent
Are ions solute or solvent?
Solute
**Soluble in water
Polar ions want all of their surface exposed to water therefore they are
Hydrophilic
Oil is an example of what type of molecule
Non-polar molecule because it is hydrophobic, water fearing
Aggregate, or clumps together to minimize their disruption of hydrogen bonding in water
Nonpolar molecules
Because they are hydrophobic, water fearing
What does water cause nonpolar molecules, such as oil to do
Aggregate, or push together
What determines the PH of a solution?
Concentration of H+ and OH-
PH measures
The # or concentration of protons and hydrogen ions
Based on a Ph scale
0=
7=
14=
0 is most acidic
7 is neutral
14 is most basic
Substance resistant to PH change
Buffer
What does a buffer do when pH is too high or acidic
Releases H+
What does a buffer do when pH is too low or basic
Absorbs H+
Maintains constant pH
Buffer
Substance that dissolves in water to increase H+ concentration
Acid
A substance that combines with H+ when dissolved in water, thus lowering H+
Base
True or false
Living organisms are not sensitive to pH change
False
living organisms are very sensitive to pH change
Blood pH is maintained by which to buffers
Carbonic acid
Bicarbonate
True or false
The pH inside almost all living cells, and in the fluid surrounding cells in multicellular organisms,is fairly close to neutral, 7.
True
Is CO2 basic?
No. CO2 is acidic
In our bodies CO2 is converted to
Bicarbonate
What does bicarbonate do in our body
Transfers CO2 to the lungs so that we can breathe it out
If blood is too acidic bicarbonate will add or retain a_________________ to form _____________________.
Proton
Carbonic acid
If too basic carbonic acid can release a____________ to form ________________.
Proton
Bicarbonate
Can form chemical compounds
Are chemically reactive
Can form bonds with other atoms
Atoms that have unfilled electrons cells
Arrange states of water from most dense to least dense
Sold
Liquid
Gas
Liquid - water is more dense than ice
Solid (ice)
Gas
Made of two or more atoms held together by chemical bonds and stable association. The Atoms may or may not belong to the same element
Molecule
Arrange least to greatest based on electronegativity
H,C,O,N
H
C
N
O
Van der waals attraction
Weak attraction between atoms due to oppositely polarized electron clouds
Attraction between covalently bound H atom with a slight positive charge and another covalently bound atom with a slight negative charge
Hydrogen bond
Hydrophobic interaction
Nonpolar regions of a molecule are forced together in order to minimize contact with water molecules
Elements possessing all 8 valence electrons are said to be
Inert
Noble gases
Rank the following bonds and interactions in order from strongest to weakest starting with the strongest at the top
Ionic bond Hydrogen bond Covalent bond Van der walls attraction Hydrophobic interaction
Covalent bond
Ionic bond
Hydrogen bond
Hydrophobic interaction
Van der waals attraction
Cohesion
Plant leaves pull water up from roots
Many types of ions and molecules move freely in cells, permitting a diverse array of chemical reactions
Solubility
Why is H2 stable? (, a molecule formed by two hydrogen atoms )
Held together by covalent bond
No net charge
No unpaired electrons
Water is polar
True or false
True
O2, CH4, N2 are all nonpolar
True or false
True
Hydrogen atoms always have one proton
True/false
True
Ex: molecular formula
H2
Elements in the same chemical group have the same bonding properties because they have the same number of valance electrons
True/false
True
The number in configuration of electrons determine and elements
Chemical properties
Hydrogen < single covalent < double covalent < triple covalent
These bonds are arranged from weakest to strongest
True or false
True
Chemical bonds are broken and new bonds are formed on a
Chemical reaction
One____________ of the element carbon contains 6.02 x 10^23 atoms of carbon
Mole
The pH up of the solution is defined as
The negative logarithm of the hydrogen ion concentration in the solution
For most of the on the elements in living organisms
Hydrogen ,oxygen , nitrogen and carbon
Water rises inside a glass tube with narrow diameter due to
Water molecules adhere to the surface of the glass
Element
Substance that cannot be broken down into simpler substances by ordinary chemical means
Trace elements
Present in tiny amounts
Play cry or ole in living processes
The ability of water to rise inside a tube of narrow diameter against the pull of gravity is called
Capillary action
Dalton =
Atomic mass
Surface tension of what is due to
The cohesion of water molecules
The property of ______________ is a measure of how difficult it is to stretch or break the surface of a liquid
Surface tension
Polar molecules
Attracted to other polar molecules
Electrically neutral
Same number of protons and electrons
When writing out structural formulas, covalent bonds are represented by the
Lines between atomic symbols
Hydrogen bond can form between partial negative ___________ atom of one water molecule and partial positive ___________ atom of another molecule
Oxygen
Hydrogen
Non polar covalent bond
Equal sharing of one or more pairs of electrons
Hydrocarbon chains are considered nonpolar
True
Buffers stabilize pH by releasing hydrogen ions when a base is added and absorbing hydrogen ions when an acid is added
True
Bond formed between two hydrogen atoms
Nonpolar covalent
A substance whose molecules are made of atoms of more than one element held together by chemical bonds is called
Compound
Ionic compounds generally exist as individual ions
True
