Chapter 2 Flashcards
the smallest identifiable unit of an element
atom
the matter that reacts
reactants
the matter that forms
product
The theory that all matter is composed of
atoms originated from several observations
and laws.
atomic theory
In a chemical reaction, matter is neither
created nor destroyed.
law of conservation of mass
law of conservation of mass
In a chemical reaction, matter is neither
created nor destroyed.
All samples of a given compound, regardless of
their source or how they were prepared, have the
same proportions of their constituent elements.
Law of definite proportions
When two elements (call them A and B) form
two different compounds, the mass of element
B that combine with 1 g of element A can be
expressed as a ratio of small whole numbers.
Law of multiple proportions
partially evacuated glass
tube called a
cathode ray tube
a beam of particles
cathode rays
negatively charged electrode
cathode
positively charged electrode
anode
a fundamental property of some of the particles that compose atoms and results in attractive and repulsive forces between hose particles
electrical charge
attractive and repulsive forces
electrostatic forces
the area around a charged particle
electric field
fundamental charge
–1.6 × 10–19
proposed that the negatively
charged electrons were small particles held
uniformlywithin a positively charged
sphere.
J.J. Thomson
directed
positively charged particles at an ultra thin
sheet of gold foil.
Ernest Rutherford
what did oil drop experiment do
deduce that the charge of a single electron
what did oil drop experiment do
deduce that the charge of a single electron Z
the emission of small energetic particles from the core of certain unstable atoms
radioactivity
a small core called a
nucleus
positively charged particles
protons
neutral particles within the nucleus
neutrons
the mass of a proton
1.67493 x 10 to the negative 27th power kg`
the mass of a neutron
1.67493 x 10 to the negative 27th power kg`
the mass of an electron
9.1 x 10 to the negative 31st power kg
unit to express the mass
atomic mass units (amu)
the most important number to identify an atom is
the number of protons
The number of protons in an atom’s nucleus is its
atomic number
what is the symbol fo 4th atomic number
Z
He
Helium
Helium
He
H
Hydrogen
Hydrogen
H
Li
Lithium
Lithium
Li
Be
Beryllium
Beryllium
Be
B
Boron
Boron
B
C
carbon
Carbon
C
N
Nitrogen