Topic 0- Earth Flashcards
describe the structure of an atom
in the centre of the atom is the nucleus, which contains protons (positive charge) and neutrons (no charge). Orbiting the nucleus is a series of shells, which hold electrons (negative charge). The electrons are much smaller than the protons and neutrons. The first shell outside the nucleus can hold 2 electrons, the second can hold 8 and the third can hold 8.
what is the relative mass and charge of a proton?
relative mass: 1
charge: 1+
what is the relative mass and charge of a neutron?
relative mass: 1
charge: 0
what is the relative mass and charge of an electron?
relative mass: 0
charge: 1-
what is the atomic number?
the number of protons in the nucleus of an atom
what is the mass number?
the number of protons + the number of neutrons in the nucleus of an atom
what are isotopes?
atoms that have the same atomic number but different mass numbers. This is because they contain the same number of protons but different numbers of electrons
what is relative atomic mass?
relative atomic mass is calculated from the masses and relative abundances of all the isotopes of a particular element. It is usually given in the symbol Ar.
how is the periodic table arranged?
it is arranged in periods (horizontal) and groups (vertical) in order of atomic number
what is another word for the outer shell electrons?
valence electrons
how do you deduce the number of outer shell electrons of an element from its position in the periodic table?
the number of outer shell electrons is the same as the group number on the periodic table
what is the symbol for relative formula mass?
Mr
how do you calculate relative formula mass?
add up the relative atomic masses of all the atoms present in the formula
