Chemistry Chapter 5
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Chemistry Chapter 5
chemistry chapter 5
Alkaline earth metal
what is an atom?
the smallest particle of an element that retains the identity of the element
what is an electron?
a negatively charged particle within the atom
on energy level
what is a subatomic particle?
a particle that is smaller than the atom
what is the nucleus?
in chemistry, the positivley charged centre of an atom
is comprised of protons and neutrons
what is a proton?
a positively charged particle that is part of every atomic nucleus
same amount of protons as electrons in an atom
what is a neutron?
an uncharged particle that is part of almost every atomic nucleus
atomic mass-atomic number=number of neutrons
what are energy levels?
a possible level of energy an electron can have in an atom
an electron must absorb energy to move up a level
what is an atomic number?
the number of protons in the nucleus of an atom or the number of electrons
what is a mass number?
the sum of the number of protons and the number of neutrons in the nucleus of an atom
what is an isotope?
one of two or more forms of an element that have the same number of protons but a different number of neutrons
is the reason for decimals on mass numbers
what is the bohr-rutherford diagram?
indicate number of protons and neutrons in nucleus
what is atomic mass?
the average mass of the naturally occuring isotopes of an element
elements are placed in order of increasing atomic mass on periodic table.
number of protons and neutrons in nucleus
what is the periodic table?
a system for organizing the elements into columns and rows, so elements with similar properties are in the same column
what is a metal?
typically, an element that is hard, shiny, malleable, and ductile, and is a good conductor of heat and electricity
eg. copper, nickel
what is a non metal?
typically, an element that is not shiny, malleable or ductile, and is a poor conductor of heat and electricity
what is a metalloid?
an element that shares some properties with metals and some properties with non metals
eg. antimony, silicon
what is a period?
a horizontal row of elements in the periodic table
numbered from 1 to 7
what is a group?
a vertical column of elements in the periodic table
numbered from 1 to 18
also called a family
have very similar physical and chemical properties
what is a valance electron?
an electron in the outermost occupied energy level of an atom
what are Alkali Metals?
the elements in group 1(except for hydrogen).
have low melting points
soft enough to be cut with a knife
highly reactive with water and oxygen
eg. lithium, sodium, potassium
what are alkaline earth metals?
elements of group 2
highly reactive, but less than alkali metals
if heated, will burn in air- combustible
often used in fireworks
produce bright flames
eg. beryllium, magnesium, calcium
what are halogens?
elements of group 17
melting points increase as you move from top to bottom of group
eg. gases are; florine, bromine, liquid is bromine, iodine is solid at room temperature
what are noble gases?
elements of group 18
main property is non reactivity
odorless, and colourless at room temperature
eg.helium, neon, xenon