Chemistry Flashcards
Atom Nucleus, atomic number, atomic mass, mass number
dense center of atom where protons and neutrons are, number of protons in atom, average mass of all isotopes of an element, number of protons and neutrons in an atom
valence electron, isotope, ion
electron in the outermost energy level of an atom, atoms of the same element with different #s of neutrons, unequal # of electrons and protons
the charge of a proton is ___ and the charge of an electron is ___
positive, negative
the little number at the top left, bottom left of an element symbol
mass number, atomic mass
number in decimals below the element symbol
atomic mass
what do neutrons do for an atom
hold it together
why can’t atoms get bigger when neutrons are added
the neutrons turn to protons
radioactive
there are not enough neutrons to hold the protons together
Shell 1: _______ electrons
Shell 2: _______ electrons
Shell 3: ___________ electrons
Shell 4: ____________ electrons
2, 8, 8, 18
how many elements on the periodic table
118
law of conservation of matter
matter cannot be created or destroyed
4 signs of a chemical change
heat, light, sound, smell, precipitation, bubbling/fizzing
open system, closed system
open systems allow matter to enter and exit while closed systems do not
chemical vs. physical change
physical changes the appearance of matter but not its composition while chemical changes the composition (aka the properties of the substance)
compound, mixture, homogeneous mixture, heterogeneous mixture
substance that is formed from different elements chemically binding, a material composed of two or more simpler substances, a mixture that looks uniform throughout, a mixture that does not look uniform throughout
