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the periodic table
chapter 25
Question | Answer |
---|---|
periodic means | at regular intervals |
in the periodic table elements are arranged in order of | increasing atomic mass |
Dmitri Mendeleev | made the first periodic table |
an element is a substance made of | one type of atom |
vertical columns are called | groups or families |
horizontal rows of elements are called | periods |
noble gases are also called | inert gases |
transition metals are found | in the middle of the periodic table |
a diagram of an atom is also called a | Bohr diagram |
atomic number is the number of | protons or electrons |
mass number is the number of | protons and neutrons |
number of electrons on shell 1 | 2 |
location of protons and neutrons | nucleus |
to find the number of neutrons | subtract the atomic number from the mass number |
number of electrons on shell 2 and 3 | 8 |
atoms of elements in group 1 | lose one electron to become a 1+ positive ion |
atoms of elements in group 2 | lose two electrons to become a 2+ ion |
atoms of elements in group 3 | lose three electrons to become a 3 + ion |
atoms of elements in group 4 | share electrons to form covalent bonds |
atoms of elements in group 5 | gain 3 electrons to form a 3- ion |
atoms of elements in group 6 | gain 2 electrons to form a 2- ion |
atoms of elements in group 7 | gain 1 electron to form a 1- ion |
atoms of elements in group 8 do not react as | their outer shell is full |
the formula for methane is | CH4 |
the formula for ammonia is | NH3 |
an ionic bond is formed when | positive and negative ions attract |
an ion is | a charged atom |