CHAPTER 2 CHEMISTRY OF LIFE Flashcards
MATTER
is anything that takes up space and has mass. It is helpful to remember that matter can exist in a number of forms, including as a solid, gas, liquid, or plasma.
Elements
cannot be broken down by chemical means. A pure substance of one kind of atom
Atoms
the smallest unit of an element that still retains the chemical and physical properties of the element.
How do atoms of different elements differ?
in the number of protons & neutrons they have
Parts of an Atom
Protons: positive charge
Neutrons: neutral charge
Electrons: negative charge
Why does an atom always have the same number of protons and electrons ?
so the charge on an atom is neutral
Structure of an atom
the nucleus is a central core containing protons and neutrons
the electrons are arranged in orbitals around the nucleus
common elements in inorganic molecules
K = Potassium Na = Sodium Fe = Iron Cl = Chlorine Ca= Calcium
common elements in organic molecules
C = Carbon H =Hydrogen O =Oxygen N = Nitrogen P =Phosphorus S = sulfur
An Atom will always contain the same number of …
protons & electrons
Isotopes
atoms of the same atomic number but have different atomic mass because the number of neutrons differ
Radioactive isotopes
are useful in dating old objects
Radiation
can be harmful by damaging cells and DNA and or causing cancer
Ions
atoms that have gained or lost electrons; this makes them either positively or negatively charged particles
Ionic bond
occurs between ions of the opposite charge
Covalent bond
when two atoms share electrons. Strongest bond
Hydrogen bond
forms between slightly positive (partial + charge) and slightly negative (partial – charge) . usually occur between a hydrogen and either an oxygen or a nitrogen atom, which is sometimes called an electronegative atom. The weakest bond.
Electronegative atom
tends to attract electrons
The most common in biological atoms are O (oxygen) & N (nitrogen)
solute
substance dissolved in a liquid
solvent
the liquid the substance is dissolved in
solution
a liquid (solvent) containing dissolved substances (solute)
aqueous solution
a solution made with water