(LE 1) Chemical Composition of the Body Flashcards
What are atoms?
Smallest unit of chemical elements composed of 3 subatomic particles. normally contain equal amount of protons and electrons
What are the charges of the subatomic articles that make up an atom? What are their masses? What are their functions?
What is an ion?
molecule with a + or - charge
What is a cation? provide two examples
molecule with a positive charge (e- donor)
e.g. Na+, Ca2+
What is an anion? provide two examples
molecule with a negative charge (e- acceptor)
e.g. Cl-, NO3-
What is atomic number?
number of protons in an atom. Identity of an atom
Define element
classification of atoms based on their atomic number
What is an isotope? Provide an example
Atoms of a single element with different number of neutrons in the nucleus
What is mass number?
number of protons + number of neutrons in the nucleus
What is atomic mass?
mass of an atom
What unit of measurement is used for atomic mass?
Dalton
What is atomic weight?
The average mass number of the isotopes. (which isotope is most common)
Can you determine the number of protons, electrons, neutrons from the atomic weight, atomic number?
Yes for most common isotope; atomic number = # of protons which has equal # of electrons.
Neutrons = Atomic weight - atomic number
What is electron energy levels? How many electrons can each hold?
Electron’s orbit around the atom (electron shell)
1st = 2 electrons
2nd and 3rd = 8 electrons
Define stable atoms
atoms that have max number of electrons in their outer shell
Define unstable atoms
atoms with unfilled outer energy levels
What is a valence electron?
electrons in unfilled outer shells which participate in bonding
What is a chemical bond?
interactions between unstable atoms that hold them together
What are three types of chemical bonds? provide examples that use those bonds
Ionic bond - Na+Cl-
Covalent bond - C6H12O6
Hydrogen bond - H2O molecules
How do ionic bonds form?
formed by the attraction of + and - charges. Dissociate in water
How do covalent bonds form?
occur when atoms share valence electrons
What are polar covalent bonds? Provide examples
Unequal sharing of electrons pulled more toward one atom. (partial charges)
Oxygen, nitrogen, and phosphorus have strong pull, tend to form polar molecules
How do hydrogen bonds form? What characteristic of water does it facilitate?
When H forms polar bond with another atom, it takes on a slight + charge, making it attracted to any nearby negatively charged atoms
creates surface tension
What is an acid? Base?
Acid: release protons (H+) in a solution (proton donor)
Base: lower H+ levels of a solution (proton acceptor)
