Chapter 2: Chemistry Flashcards
Matter
A physical substance that takes up space and has mass
Element
A pure form of matter containing only one kind of atom
Earth is made up of- 100 elements, plus some others
( periodic table)
Atom
Is the smallest particle of an element
cannot be broken down by ordinary chemical processes
nucleus contains the mass
Subatomic Particles
Protons, Neutrons, and Electrons
Protons
- make up the nucleus
- use to determine identity
- has mass
- does not change
Neutrons
- no charge
- has mass
- number can change
Electrons
- mass is (negligible): to small to change anything
- number can change
Elemental composition of organisms
Atom(hydrogen) Molecule(water) cell(neuron) organ(brain) organism
CHNOPS
carbon, hydrogen, nitrogen, oxygen, phosphorus, sulfur
make 98% of most living things
number of elements important to life
25
atomic number
number of protons
atomic mass
number of protons and neutrons
isotopes
atoms of a particular element all have same number of protons but they can differ in the number of neutrons EX: Carbon carbon -12 (stable) carbon -13 (stable) carbon -14 (unstable) radioactive
Electrons /
orbits around the nucleus - Shells
inner shells may hold up to 2 electrons and outer shells may hod up to 8 each
Valence electrons
electrons in the outermost shell
Chemical Bonds
Bonds between atoms are form of chemical energy
Atoms form bonds because doing so moves them to a more stable state
Types of bond
covalent
ionic
hydrogen bonds
Covalent bonds
Sharing of electrons between atoms
Strongest
Ionic Bonds
Transfer of electron between atoms
Ion= charged atom
Oppositely charged ions attract
Strong
Hydrogen bonds*
bonds between already covalently bonded hydrogen and an electronegative atom
Polarity*
Polar molecules= different areas of the molecule have slightly different charges
Hydrophilic
water-loving
Hydrophobic
water-hating
Water
vertebrate animals 70% - 80% water
terrestrial plants 90%
Molecule
A group of atoms bonded together- the smallest fundamental unit of chemical compounds
