Scientists
Imagined an atom as a sphere of positive charge with electrons scattered throughout, like plums in a pudding
J.J. Thomson
Smallest part of an element that retains identity in a chemical reaction
An atom
True or False
Atomic number = # of neutrons
False
What subatomic particle has a negative charge?
electrons
Luster, shiny, good conductors of heat and electricity
Metals
Atoms are tiny, hard spheres that cannot be split up.
John Dalton
True or False
Chemical reactions occur when atoms are separated, joined, or rearranged.
True
Atom of the same element that have the same number of protons but different # of neutrons is called.
An Isotope
An atom that has gained or lost and electron.
An Ion
Group 1 on the periodic table is called.
Alkali Metals
Thomson discovered negatively charged particles, which he called electrons using what piece of equipmemt?
Cathode Ray Tube
Neutral atom
Same number or protons and electrons
Protons and neutrons are found where?
The nucleus
An atom that has gained an electron is called.
An anion
Some properties of metals and some of nonmetals
Metalloids / Semi-metals
During the Gold foil experiment, he concluded that atoms must have a tiny, dense, positively charged center called the nucleus.
Rutherford
This particle identifies an element.
proton
What does the number 14 and 15 represent in the following examples.
N-14 and N-15
Mass Number
An atom that has lost an electron is called.
A cation
Group 17 on the periodic table is called.
Halogens
Discovered the neutron had approximately the same mass as protons but no charge.
James Chadwick
# of protons + # of neutrons
Mass Number
Isotopes are chemically alike b/c they have identical number of what?
p+ and e-
Write the nuclear symbol for an atom that has 28 protons, 31 neutrons and 26 electrons?
5928Ni 2+
Group 2 on the periodic table is called.
Alkaline Earth Metals