1. Atoms and Molecules Flashcards
Definition of Biology
Biology - the study of living organisms that are subject to the laws of chem and phys
Key concepts about atoms and molecules in biology
- Matter consists of chem elements in pure form / combinations called compounds
- An element’s properties depend on the structure of its atoms
- Formation + function of molecules depend on chemical bonding between atoms
- Chemical reactions make and break chemical bonds
Define element
Element - a substance that cannot be broken down into another substance by a chemical reaction
Define compound
Compound - substance consisting of 2+ different elements combined in a fixed ratio
What are the biological elements and how many % of living matter do they make up?
C, H, O, N
96%
Define atom
Atom - the smallest unit of an element that retains the chemical properties of the element
Explain the structure of an atom
Nucleus = protons + neutrons (same # as protons unless isotope) -> atomic mass
Electrons in atomical orbitals -> little weight - not considered, same # as protons
Define potential E
Potential E - E that matter possesses because of its location / structure
Which parts of an atom are involved in chemical reactions?
Only electrons - those atoms reactive which have unpaired e- in the valence shell
What is the source of potential E in e?
Distance from the nucleus - the greater potential E as the e- moves further form the nucleus
Which E state is preferred by matter?
Matter moves to the lowest state of E
What determines chemical behaviour of an atom?
Determined by the distribution of e- in e- shells
Define covalent bond
Covalent bond - sharing a pair of valence e- by two atoms
How are e- distributed in ionic bonds?
More EN atoms completely removes e- from less EN atom
The types of ions
Atoms or molecules can be ions
