chemistry Flashcards
chemistry
study of matter
matter
anything that takes up space
name three states of matter
solid, liquid, and gas
element
matter composed of atoms that have the same number of proton charges in the nuclei
how many elements are required in a living organism? name the 4 basic elements needed and their symbol
carbon- C
Nitrogen-N2
oxygen-O2
hydrogen-H+
what are the basic untis of matter
atoms
what is an atom
an atom is the smallest unit of an element with that elements characteristics
what is the number of protons equal to in an atom
electrons
what is the atomic number
number of protons
what is the atomic mass
sum of protons and neutrons
isotope
different form of the same atom
difference between radioisotopes and radioactivity
radioisotopes- unstable isotopes(usually used to destroy cells
radioactivity- process of spontaneous breakdown(putting to much in nucleus
half-life
the time taken for the radioactivity of a specified isotope to fall to half its original value (ex :Chernobyl)
what is a chemical bond
electric attraction between atoms
what does an atom do if it has an ionic bond with another atom
donates a electron on it outer shell (has only one electron on outer shell) to another electron that has 7 electron on their outer shell (ex: NaCl)
what does an atom do if it has a covalent bond with another atom
two atoms join together and share the electrons on their outer shell (ex:O2)