Chemistry - Unit 2

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what are the 3 particles in the atom and their charges?

proton: +1

neutron: no charge

electron: -1

where is almost all of the mass located in an atom and what particles are there?

the nucleus which consists of protons and neutrons

how is the mass number calculated and why are there only two particles taken into account?

the mass number is the total number of protons and neutrons because they both have a mass of 1 amu and electrons basically have 0 mass

what are the differences between ions and isotopes?

ions have different numbers of electrons than protons which results in a positive or negative charge

isotopes have the same number of protons but different numbers of neutrons

define cation

a positive ion resulting from the loss of electrons

define anion

a negative ion that is produced when an atom gains electrons

where are the groups and periods on the periodic table?

periods: rows

groups: columns

on the periodic table, what is 1A?

alkali metals

on the periodic table, what is 2A?

alkaline earth metals

on the periodic table, what is 6A?

chalogens

on the periodic table, what is 7A?

halogens

on the periodic table, what is 8A?

noble gases

describe Dalton’s contribution to our understanding of the atom

proposed the first modern atomic theory which said that matter is made up of atoms, atoms of the same element are identical, and compounds are combinations of atoms in fixed rations

describe Thompson’s contribution to our understanding of the atom

discovered the electron through his experiments with cathode rays, leading to the "plum pudding" model of the atom, where electrons were thought to be embedded in a positively charged "pudding"

describe Millikan’s contribution to our understanding of the atom

conducted the oil drop experiment to determine the charge and mass of an electron, providing a precise value for the charge of an electron

describe Rutherford’s contribution to our understanding of the atom

conducted the gold foil experiment, which led to the discovery of the atomic nucleus and proposed a model of the atom with a dense, positively charged nucleus surrounded by electrons

describe Planck’s contribution to our understanding of the atom

developed the concept of quantized energy levels, contributing to the foundation of quantum theory

describe Bohr’s contribution to our understanding of the atom

developed the Bohr model of the atom, which introduced the concept of electrons orbiting the nucleus in discrete energy levels

cathode rays are __________

electrons

the gold foil experiment performed in Rutherford's lab __________

led to the discovery of the atomic nucleus

the atomic number indicates _________

the number of protons or electrons in a neutral atom

the nucleus of an atom contains _________

protons and neutrons

of the following, the smallest and lightest subatomic particle is the _________

electron

all atoms of a given element have the same __________

number of protons

isotopes are atoms that have the same number of __________ but differing number of _________

protons and neutrons

different isotopes of a particular element contain the same number of _________

protons

different isotopes of a particular element contain different numbers of __________

neutrons

nonmetals can be __________ at room temperature

solid, liquid, or gas