topic 1 atoms elements etc and german vocab Flashcards
what is an element
a substance that cannot be broken down into anything simpler
what is a compound
these substances contain 2 or more elements chemically combined
the elements in a compound are in a fixed ratio
what is a mixture
these substances contain two or more elements in a variable ratio and are not chemically combined
what is a molecule
when atoms join together the group is called a molecule eg O2 or H2O
what is the relative mass of a proton
1
what is the relative mass of a neutron
1
what is the relative mass of an electron
0
what is the relative charge of a proton
+
what is the relative charge of a neutron
0
what is the relative charge of an electron
-
how do you calculate relative mass
(a × percent it is found) + (b × percent it is found) / 100
eg Cl with mass of 37 found 50%
Cl with mass of 35 found 50%
what did democritus propose
proposed matter could not be divided into smaller pieces forever
matter was made from small hard particles he called atoms
what did john dalton introduce
the first atomic theory
1. atoms are tiny invisible particles
2.atoms of one element are all the same
3.atoms of different elements are different
4. compounds are formed by combining atoms
what did JJ Thomson discover and how
electrons with cathode rays
what did Niels Bohr propse
shells
every atom has a specific number of electron shells
what are isotopes
atoms of the same element with the same number of protons but with different masses
how many electrons can the first shell hold
2
how many electrons can the second (and every other level apart from 1) hold
8
what is an ion
a charged atom
what is a group on the periodic table
a vertical column of elements
what is a period on the periodic table
a horizontal row of elements
Unterricht
lesson
Druck
pressure
Sprache
language
