chem test 1
An ion that consists of 7 protons, 9 neutrons, and 10 electrons has a net charge of
-3
Compounds are
2 or more elements chemically combined
What is the charge of the nucleus of a copper atom?
29
Temperature
A measure of the average kinetic energy of the molecules of a substance.
endothermic
Absorbs heat
Which emission causes the atomic number of a nuclide to decrease by 2 and its mass number to decrease by 4?
Alpha Particle
Any process that leads to the production of another element is called:
Transmutation
What cannot be broken down by chemical means?
an element
The elements on the Periodic Table of the Elements are arranged in order of increasing
atomic number
J.J. Tomson (1897)
cathode ray experiments, negatively charged particle, named electron
physical change
change in a substance that does not change its identity, no new substance
chemical change
changes in which new substances are formed
Elements cannot be decomposed by
chemical means
Two elements together make a-
compound
Becquerel
discovered radioactivity
a charged atom is called an
ion
Matter is anything that has ____ and takes up ____.
mass and take up volume
heterogeneous
more than one set of properties, of different kinds
The results of the gold foil experiment led to the conclusion that an atom is
mostly empty space and has a small, positively charged nucleus
Atoms are neutral when the number of
protons equals the number of electrons
An unstable nucleus spontaneously releases a positron. This is an example of
radioactive decay
Ernest Rutherford
realized that atom was mostly empty space and had a small positively charged nucleus
proton identified by :
rutherford
mixtures are
substances that are physically but not chemically combined
ionizing power
the ability of radiation to damage molecules (molecules lose electrons)
penatrating power
the ability of radioactive particles to move through material
Two atoms that are different isotopes of the same element have-
the same number of protons but a different number of neutrons.
A change in the nucleus of an atom that converts the atom from one element to another element is called
transmutation
homogeneus
uniform throughout
John Dalton
Englishman, proposed an atomic theory
Democritus
Greek philosopher small indivisible particle called atoms
Which statement describes the location of protons and neutrons
Protons and neutrons are in the nucleus.
exothermic
Releases heat