Biology Chapter 2 Flashcards
What is an Atom
The smallest known unit of measurement, it cannot be made or destroyed
What does an atom contain?
A nucleus with neutrons and protons, and electrons circling around.
proton versus electron
protons are positively charged, electrons are negatively charged
What is an Element
a pure substance made up of only one type of atom
How many naturally occurring elements are there?
92
atomic number
how many protons there are in the atom, this is shown in the top left corner of the element in the periodic table.
atomic mass
the number of protons plus the number of neutrons
What is a chemical compound
substance made of two or more atoms from elements
What are the types chemical bonds
covalent, ionic, and hydrogen
what is a covalent bond
a bond made by sharing electrons
What is an ionic bond
a bond made by transferring electrons
What is a hydrogen bond
a bond made between polar molecules, one is positively charged and one is negatively charged so they attract
polar versus non-polar molecules
polar molecules have an unequal distribution of electrons and therefore have a different charge in different parts
compound versus molecule
a compound is the JOINING of the atoms in elements, a molecule is a group of atoms held together by a covalent bond
van der wals forces
Weak attractions when molecules are close together
What are two unique properties of water?
Storage of energy (moderates earths temp.)
Cohesion and Adhesion (water attracts to both itself an d other substances
cohesion versus Adhesion
Cohesion is the attraction of a molecule to itself, adhesion is the opposite
Solution versus Mixture
A solution occurs when molecules are equally distributed with one another
solute versus Solvent
The solute is dissolved in the solvent