Chapter 2 Chemistry of life Flashcards
Element
substance cannot be broken down to other substances by a chemical reaction. all atoms have same number of protons
compound
substance with 2 or more different elements in a fixed ratio
Atom
smallest particles that retain chemical elements. cannot be broken down by chemical reactions
Anatomy of atom helium
++ proton and neutron in nucleus
- electrons
subatomic particles
neutrons, protons, and electrons
Atomic number
number of protons
how to find atomic mass
protons + neutrons
atomic # of Hydrogen
atomic number= 1
atomic # of Carbon
atomic number= 6
atomic # of nitrogen
atomic number= 7
atomic # of Oxygen
atomic number= 8
biologically important elements
“CHNOPS”
Carbon, Hydrogen, Nitrogen, Oxygen, Phosphorus, Sulfurs
trace element: Iodine Deficiency
results in enlarged thyroid gland.
trace element; critical for breathing
Iron, attached to hemoglobin to bring in the oxygen
Isotopes
elements with the same # protons but different # of neutrons
what results from a chemical bond
attraction between atoms
incomplete valence shells
can share, trade, or transfer valance electrons
covalent chemical bonds
share a pair of valance electrons between 2 atoms
what happens to electron in an ionic chemical bond
trade off/ receive
hydrogen chemical bond
weak, attracted by partial charges between hydrigen and electronegative atom
Electronegetivity
each atom, the density and # of electrons in valance shell determines how strongly the atoms hold on to the electrons
higher density and complete valance shell
higher electronegativity
electronegativty of oxygen and hydrogen
oxygen- most electronegative
hydrogen- least electronegative
polar
partial charge
Ionic Bonds
cation and anions attract each other
Cation
+ charged after giving away - electron
Anion
receive electron - electron
Two or more atoms held together by covalent bonds constitute a
molecule
