atoms , the periodic table and chemical bonding Flashcards
what are atoms made up of ?
protons , neutrons and electrons
what is the atomic number of an atom ?
the number of protons and electrons it has in its nucleus
what is the mass number of an atom ?
the number of protons plus the number of neutrons in its nucleus
what are isotopes?
atoms of the same element , which have a different numbers of neutrons
what charge does the proton have ?
positive
what charge does the electron have ?
negative
what charge does the neutron have ?
neutral
what makes each atom different ?
each atom is different because each has its own number of protons in its nucleus
the first shell ( n=1) can hold a maximum of how many electrons ?
2
the second shell ( n =2) can hold a maximum of how many electrons ?
8
the arrangement of electrons in an atom is called its what ?
electronic configuration
what do atoms in the same group have in common?
they have the same number of electrons in their outermost shells
what is a group ?
a vertical column of elements that all have the same number of electrons in their outermost shells.
what is a period ?
a horizontal row of elements in the periodic table
what do all elements in a period have in common
they have the same number of electron shells .
what is group 1?
the alkali metals
what is group 2?
the alkaline earth metals
what is group 3?
the halogens
what is group 4?
the noble gases
how are elements stable ?
elements that have 8 electrons in their outer shells are very stable ( expect for helium which has a stable outer shell of 2 electrons)
what is the octet rule
atoms bond together so that each atom gets an electron arrangement with 8 electrons in its outermost shell
what is ionic bonding ?
this is a bond formed when one atom gives away one for two outer electrons , and the other atom takes them .
what is an ion ?
an ion is a charged atom or group of elements
what is an ionic bond ?
an ionic bond is formed by the force of attraction between a positive and a negative ion.
