ATOMS & ATOMIC THEORY Flashcards
the branch of science that deals with the identification of the substances of which matter is composed; the investigation of their properties and the ways in which they interact, combine, and change; and the use of these processes to form new substances.
CHEMISTRY
first to hypothesized the atom and said
“everything you see around you is made up of smaller objects”
DEMOCRITUS
proposed the atomic theory in 1808. “father of atomic theory”
JOHN DALTON
SMALLES PARTICLE OF AN ELEMENT
ATOM
ATOM CAME FROM THE GREEK WORD ____ THAT MEANS IN INDIVISIBLE
ATOMOS
WHO DISCOVERED THE “ELECTRON”
SIR JJ THOMSON in 1897
CHARGE OF AN ELECTRON
-1.60 × 10−19 C
MASS OF AN ELECTRON
9.109X10-31 Kg
1amu = ____Kg = 1u (unified atomic mass unit)
1.662 x 10-27
WHO DISCOVERED PROTON
ERNEST RUTHERFORD IN 1911
CHARGE OF PROTON
+1.6 x 10-19 C
MASS OF A PROTON
1.6725 x 10 -27 Kg
WHO DISCOVERED NEUTRON
JAMES CHADWICK IN 1932
CHARGE OF A NEUTRON
0
MASS OF A NEUTRON IN Kg
1.67 x 10 -27
how many times larger/smaller is a proton compare to an electron “Mp=_____Me
1836
compare the mass of a neutron (Mn) with an electron (Me) “Mn=___Me”
1839
atomic number represents the number of ___ in the nucleaus of an atom
protons
a neutral atom means that the no. of protons is _____ the no. of electrons
equal to
____ = no. of protons + no. of neutrons
Mass number / MN (mass number is always a whole number)
atoms with the same no. of protons but different numbers of neutrons
ISOTOPES
THE WEIGHTED AVERAGE OF ALL THE MASS NUMBERS OF NATURALLY OCCURING ISOTOPES OF AN ELEMENTS
ATOMIC MASS
DIFFERENTIATE ATOMIC MASS AND MASS NUMBER
ATOMIC MASS= THE WEIGHTED AVERAGE OF ALL THE MASS NUMBERS OF NATURALLY OCCURING ISOTOPES OF AN ELEMENTS
Mass number / MN = no. of protons + no. of neutrons
