Chapter 2 Flashcards
What are the main chemical elements
Oxygen, carbon, hydrogen, nitrogen
How many and what are the “lesser elements”
8 contribute to 3.6% of body masses
Calcium, Phosphorus, potassium, sulphur, sodium, chlorine, magnesium, and iron
How many “trace” elements in the body
14 present in tiny amounts
What are atoms ?
The smallest unit of matter that retain the properties and characteristics of the element
What are the 3 subatomic particles that make up the structure of an atom ?
Small particles that compose individual atoms
1. Protons
2. Neutrons
3. Electrons
What subatomic particles are contained in the nucleus of an atom
- Positively charged protons
- neutral/uncharged neutrons
What are electrons ?
Negative charged subatomic particles that move around the nucleus of an atom
What makes the atomic number of an element ?
The number of (-) electrons = the number of (+) protons
What makes the mass number ?
The sum of protons + neutrons
These are within the nucleus
What is an isotope ?
The same element with the same atomic number (same number of electrons to protons) but has a different number of neutrons within the nuclei causing a different mass number
The number of electrons in an atom determines its ________?
Chemical properties.
This means whether it receives or donates their electrons to form a bond
What is an ion?
When there are unequal numbers of protons and electrons causing a particle to have a positive (more protons) or negative charge (more electrons)
What is ionization ?
Process of giving up or gaining electrons
What is a molecule ?
When two or more atoms share their electrons
The molecule formulated indicates the elements (oxygen) and number or atoms (2 of them to = O2)
What is a compound ?
Contains atoms of 2 or more different elements
(H20, two molecules of hydrogen and one of the element oxygen)
What is a free radical?
An atom, molecule, or ion with an unpaired electron in the valence shell
What is a valence shell ?
The outermost shell of an atom, where chemical bonds occur depending on the number of electrons there. This number identified whether it is required to donate or receive electrons
What is an ionic bond ?
Force of attraction that holds together ions of opposite charges (opposites attract)
example: Na has an extra (1) electron alone in its valence shell that it dan donate
Cl has 7 in its valence shell, open to receive the excess electron to make it stable.
The giving away causes a +1 charge ion (cation) for its “extra” donated electron while the Cl become a -1 charge (anion) for having received 1 electron.
Na (+1) attracts the Cl (-1) to form the ionic bond
What is an ionic compound ?
- When a compound (atoms of 2 or more different elements ex. NaCl) break apart into a positive or negative ion
- Known as an electrolyte when the compound is placed into a solution
- The electrons in the valence shell donate into a charge, and then attract to each other by ionic bond
Na+ + Cl- = NaCl
What is a cation and an anion
Cation is a positive charge ion, anion is a negative charge ion
What is a covalent bond?
When two or more atoms share their electrons (valence shell to become stable requires 8 electrons, they share by attaching multiple other atoms and their extra electrons till they contain 8 in the valence shell)
What is a hydrogen bond?
attracts mainly fluorine, oxygen and nitrogen
unequally causes an unshared electron pair for these atoms to make them partially - charge and the
Hydrogen become partially + charged
Why do hydrogen bonds work?
- ability for cohesion to link between molecules (like particles to stay together)
- has high surface tension
- a good solvent for ionic compounds as it can readily form hydrogen bonds with solutes creating electrolytes
Define a chemical reaction
When new bonds form or old bonds break between atoms
By metabolism, a reactant forms or breaks down into new products
What is potential energy
Stored energy
What is kinetic energy
Energy in motion
What is chemical energy
A form of potential energy that is stored in the bonds of compounds and molecules
What is the law of conservation of energy
Energy cannot be created or destroyed, but it can be converted from one form into another
Energy from one to another generally releases heat
Differentiate between exergonic chemical reactions and endergonic chemical reactions
- Exergonic reactions release more energy than they absorb (occur with breakdown or nutrients)
- Endergonic reactions absorb more energy than they release (occur with building of body structures)
Particles of matter such as atoms, ions, and molecules have ________ energy
Kinetic
What is activation energy
The collision energy needed to break chemical bonds of reactants
Initial energy is needed to start a reaction.
The reactants absorb enough energy for chemical bonds to become unstable and for valence electrons to form new combinations.
The new binds begin to form, and energy is then release to their surroundings.
How does concentration and temperature influence the chance of a collision to occur in causing a chemical reaction
Concentration: more particles of matter in a confirmed space increases the chance of collision as there is greater pressure in the space to force particles closer together so the particles will collide more often
Temperature: increase in temperature by heat energy causes particles to move rapidly causing more of a forceful collision
What is the function of a catalyst in a chemical reaction
They are chemical compound that speed up a chemical reaction by lowering the activation energy needed for the reaction to occur.
They help properly orient colliding particles (organization and precision) to make a reaction happen
Too much requirement for activation energy by temperature or concentration can kill or damage body cells as they require more energy to be used as they are slow. Catalyst prevent this.
Define a synthesis anabolism reaction
2 or more atoms, molecules, or ions combine to form new and larger molecules
They are endergonic, absorb more energy than they release
A + B -> AB
Describe a decomposition catabolism reaction
Splitting up a large molecule into smaller atoms, ions or molecules.
Exergonic reaction, as the release more energy than they absorb
AB -> A + B
Describe an exchange reaction
Consists of both synthesis and decomposition reaction, they switch partners
AB + CD -> AD + CB
Describe an exchange reaction
A synthesis and decomposition reaction, where they switch partners
AB + CD -> AD + CB