Chapter 2 - Chemical Basis of Life Flashcards
Chemistry
the branch of science that studies the composition, properties and interactions of matter
Atomic Number
the number of protons
Mass Number
the total number of protons plus neutrons
Isotopes
atoms with the same atomic number but different mass numbers due to differing amounts of neutrons
Radioactive Isotopes
unstable isotopes that experience atomic degradation which releases energy
- Releases atomic radiation
Forms of Radiation
- Alpha: consists of particles from atomic nuclei which includes two protons and two neutrons which move slowly and cannot penetrate matter
- Beta: consists of electrons(smaller) that travel faster and can more deeply penetrate matter
- Gamma: a form of energy similar to X-radiation and is the most penetrating form of radiation
Octet rule
8 electrons are required to fill the shells in most of the atoms important for living organisms, besides if atoms only have 1 shell
Inert
used to describe atoms who cannot form chemical bonds due to having outermost shells being stable
Ionic Bond
the attraction of two oppositely charged ions which are charged due to the movement of electrons
Covalent Bond
the sharing of electrons between two atoms to fill their valence shells and become stable
Nonpolar Covalent Bond
covalent bonds where atoms are shared equally due to both atoms having similar electronegativity
Polar Covalent Bond
covalent bonds between two atoms where 1 is more electronegative than another, resulting in a pull of electrons towards the more electronegative atom, creating an uneven distribution of charges
Hydrogen bond
he weak polar covalent bond between a hydrogen atom and a oxygen or nitrogen atom
Electrolytes
compounds that ionize in water due to the positive and negative ends in water molecules causing atoms to dissociate
- E.g. sodium chloride in water will dissociate into sodium and chloride ions
- Electrolyte means they can conduct an electrical current in water
Types of Electrolytes
- Acid: substance which releases hydrogen ions
- Base: substances that releases ions which combine with hydrogen ions
- Salt: substances formed by the reaction between an acid and a base