CHAPTER 2 Flashcards
particles much smaller than the atom
Subatomic particle
the smallest particle that has all the properties of an element.
Atom
-an element was composed of identical atoms that reacted the same way chemically.
- eye and hook affair
John Dalton
first periodic table of the elements.
Dmitri Mendeleev
Group 1
Group 7
Group 8 are called?
Alkali metals
Halogens
Noble gasses
all soft metals that combine readily with oxygen and react violently with water.
alkali metals,
are easily vaporized and combine with metals to form water-soluble salts.
Halogens
are highly resistant to reaction with other elements
Noble gasses
He concluded that electrons were an integral part of all atoms. He described the atom as looking something like a plum pudding, in which the plums represented nega- tive electric charges (electrons) and the pudding was a shapeless mass of uniform positive electrification
J.J thomson
-disproved Thomson’s model of the atom.
-called the center of the atom the nucleus.
Ernest Rutherford
improved Rutherford’s description of the atom. His model was a miniature solar system
Neils Bohr
The fundamental particles of an atom
electron, the proton, and the neutron.
The force that keeps an electron in orbit
centripetal force
Through this the electrons maintain their distance from the nucleus while traveling in a circular or elliptical path.
centrifugal force or flying-out-from-the-center force,
The strength of attachment of an electron to the nucleus is called the
electron binding energy,
-Atoms that have the same atomic number but different atomic mass numbers are
-contain the same number of protons but varying numbers of neutrons.
isotopes.
-Atomic nuclei that have the same atomic mass number but different atomic numbers are
-are atoms that have different numbers of protons and different numbers of neutrons but the same total number of nucleons
Isobar
-Atoms that have the same number of neutrons but different numbers of protons are
-are atoms with different atomic numbers and different mass numbers but a constant value for the quantity A–Z.
Isotones
-have the same atomic number and the same atomic mass number.
-identical atoms except that they exist at different energy states because of differences in nucleon arrangement.
Isomer
Atoms of various elements may combine to form structures called
Molecules
-is any quantity of one type of molecule
-includes more than one element
Compound
the spontaneous emission of particles and energy in order to become stable.
Radioactivity
results in emission of alpha particles, beta particles, and usually gamma rays.
Radioactive decay
an electron emitted from the nucleus of a radioactive atom.
Beta particle
is a helium nucleus that contains two protons and two neutrons.
Alpha particle
