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Science 20
Stack #15061
Science 20 Qs - Chemestry | Science 20 As - Chemestry |
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significant digits rule is ... | do not count leading zero's, but do count trailing zero's |
do not add zero's unless they are ... | significant |
put a zero in front of a decimal but _______ count it as significant | do not |
certainty rule is ... | when multiplying or deviding, round the answer to the smallest amount of digits in the question |
precision rule is ... | when adding or subtracting, round the answer to the smallest number of decimal places |
_________the last significant digit in your answer | round off |
do not round off the number until ... | the end of the question |
with scientific notation you ... | move the decimal place so that only one non - zero digit appears to the left of the decimal |
drop all ____________ zero's | non - significant |
multiply this number by 10 coefficient n, where n is... | the number of places the decimal was moved |
when the first digit after thoes retained is less than 5 ... | all digits retained remain the same |
when the first digit after thoes retained is greater than 5 ... | the last digit retained is increased by one |
there are ____ different elements | 109 |
one atom of a particular element is represented by a ... | symbol |
the symbol is either a capital letter by itsself or ... | a capital letter followed by a lower case letter |
the symbol for carbon is ... | C |
the symbol for cobalt is ... | Co |
atoms combine together to form ... | molecules |
a molecules is represented by symbols placed side by side to form ... | formulas |
different kinds of atoms combined together produce ... | a molecule of a compound |
in the formula H2O, the number 2 is called a ________ | subscript |
the subscripts in a formula tell the ______________ in the molecule | number of each kind of atom |
some molecules are made up of two or more ... | atoms of the same element combined together |
elements of the same kind form together when ... | they don't want to be alone (they are unstable and become more stable when paired) |
Dalton's atomic structure ... | invisible and round like billiard balls |
Thompson's atomic structure ... | positive sphere, embedded electrons almost like a raisin bun |
Rutherford's atomic structure .... | small positive neucleus surrounded by electrons |
Bohr's atomic structure .... | certain number of electons in quantisized energy levels |
protons and neutrons are found in the inner core of the atom called ... | the neucleus |
______ are found moving around the outside of the nucleus | electrons |