Unit 1: atoms and molecules Flashcards
what are the four most abundant elements found in our body and their percent’s?
- Oxygen (O) - 65%
- Carbon (C) - 18.5%
- Hydrogen (H) - 9.5%
- Nitrogen (N) - 3.2%
what is matter?
anything that occupies space and has a mass
What is an Element?
A pure substance that is distinguished from all other matter by the fact that it cannot be created or broken down by ordinary chemical means.
What are other elements in our body? (bonus to know percents :))
- Calcium (Ca) - 1.5%
- Phosphorus (P) - 1%
- Potassium (K) - 0.4%
- Sulfur (S) - 0.3%
- Sodium (Na) - 0.2%
- Chlorine (Cl) - 0.2%
- Magnesium (Mg) - 0.1%
What trace elements are found in our body? What is the percent that they are found in?
Boron, chromium, cobalt, copper, fluorine, iodine, iron, manganese, molybdenum, selenium, silicon, tin, vanadium, and zinc.
less than 1%
What is a molecule?
The combination of two or more atoms joined by chemical bonds
What is a compound?
a substance containing at least two different elements joined by chemical bonds
What is an inorganic compound?
a substance that does not contain both carbon and hydrogen
Examples of inorganic compounds?
- H20 (water)
- HCl (hydrochloric acid)
- CO2 (carbon dioxide)
What is an organic compound?
A substance that contains carbon-hydrogen bonds. they can be synthesized via covalent bonds within the human body.
what is a covalent bond?
Sharing of electron pairs between atoms
Example of organic compound in human body and its purpose?
C₆H₁₂O₆ (glucose) - Energy!
What is an atom?
Smallest quantity of an element that retains the unique properties of that element,
What are the subatomic particles and their charges?
Proton (positive) , neutron (neutral) , electron (negative)
What gives the mass number of an atom?
Protons + Neutrons
How do you determine what element is the atom?
The number of protons in the nucleus of the atom
The number of negatively charged electrons equals the number of ___
Protons
Two ways of drawing atom structure
Planetary model (bohr model) Electron cloud model
Why is an electron cloud model more realistic than the bohr model?
in the bohr model, the electrons orbit the nucleus in a ring like how the earth orbits the sun. Electrons do not behave this way, as they move erratically within the “electron cloud”
What gives the atoms structural stability?
The positive protons and the negative electrons attract each other, holding the atom together and keeps the electrons from straying far.
What gives an element its distinctive properties?
the unique quantity of protons (atomic number)
What is the atomic number?
The number of protons (which also means electrons)
what is the periodic table of elements
it is a table of 92 elements, some found in nature, and others unstable, experimentally discovered
how is the periodic table organized?
By atomic number
what is an electron shell?
a layer of electrons that surround a nucleus at a distinct energy level
How many electron shells can there be from the elements of the human body? How many electrons can each hold?
There can be 1 - 5 shells.
2, 8 , 18, 32, 32
What is a valence shell?
It governs the tendency of an atom to participate in chemical reactions. it is the outermost electron shell.
what happens when the valence shell is full
The atom is stable because it is unlikely to be pulled away from nucleus by the electrical charge of other atoms.
what happens when the valence shell is not full?
The atom is reactive because it will react to other atoms in ways that the valence shell will be full to become stable.
What is the octet rule?
An atom will give up, gain or share an electron with another atom so that it has 8 electrons in its valence shell.
When is an atom most stable?
When it has 8 electrons in the valence shell ( except for the first shell like helium and hydrogen)
what is anatomy
the study of parts of the body
What is Physiology
the study of the normal functioning of the body
WHat are the main components of life?
- The exchange of materials with the environment (inhalation/ exhalation)
- obtain energy from organic molecules (digestion)
- synthesize complex organic molecules (proteins, hemoglobin)
- Reproduction
- Respond to stimuli to environment
What is cell division and why does it happen?
Cell division is the ability of a single cell to divide into 2 cells, it happens because higher level organisms start off with a single cell.
