Chapter 2 Notes Flashcards
chemistry
Study of the nature of matter
matter
anything that occupies space and has mass (include solids liquids and gases in our bodies as well as surroundings)
all things are composed of
elements
elements
Basic chemical substances that make up matter
20 elements
needed by living things
which for atoms make up 95% of the human body
carbon, oxygen, hydrogen, nitrogen
atoms
tiny particles which make up elements
nucleus
Central portion, positive
parts of the atom
nucleus, electrons around the nucleus
charge of the atom
neutral
nucleus contains
protons, positively charged particles-neutrons, uncharged particles
where are electrons found
found in a cloud outside the nucleus
characteristics of electrons
very small, have a negative charge
atomic number
equal to the number of protons in its nucleus
atomic weight
average of the relative wait (mass numbers) of all the isotopes of an element, neutrons and protons
bonding of atoms
when atoms combine with each other, they gain or lose electrons, or share electrons with other atoms
electrons arranged in
shelves
first shell
two electrons
Second shell
eight electrons
third shell
eight or 18 electrons
ion
particle that gains or loses electrons
atoms that lose electrons become ______ charged
positively
negatively charged
atom that gains electrons
ions
atom with a positive or negative electric charge