Topic 2 - Atomic structure and bonding Flashcards
Topics 6-8
Elements in the periodic table are arranged in
order of increasing atomic number
The periodic table can be used to determine
whether an element is a metal or non-metal
Groups in the periodic table are
columns containing elements with the same number of outer electrons, indicated by the group number
Elements within a group
share the same valency and have similar chemical properties because they have the same number of electrons in their outer energy levels
Atoms have a nucleus containing
protons and neutrons, and electrons that orbit the nucleus
Charge of subatomic particles
Protons = 1+
Neutrons = neutral / no charge
Electrons = 1-
Mass of subatomic particles
Protons = 1
Neutrons = 1
Electrons = 0
The atomic number is
the number of protons in an atom
In a neutral atom, the number of protons and electrons are
equal
The mass number of an atom is equal to
the number of protons + neutrons
Isotopes are
atoms with the same atomic number but different mass numbers
Nuclide notation is used to
show the atomic number, mass number (and charge) of atoms
(ions) from which the number of protons, electrons and neutrons can be determined.
How many isotopes do most elements have
2 or more
What is relative atomic mass (RAM)
The average atomic mass for each element
Covalent bonds form between
non-metal atoms
A covalent bond forms when
two positive nuclei are held together by their common attraction for a shared pair of electrons
What elements exist as diatomic molecules through the formation of covalent bonds
Br I N Cl H O F
The shape of simple covalent molecules depends on
the number of bonds and the
orientation of the bonds around the central atom
Simple covalent molecules can be described as
Linear, angular, trigonal pyramidal and tetrahedral
What happens when atoms share more than one pair of electrons
they form double or triple bonds
Covalent substances can either form
discrete molecular or giant network structures
Covalent molecular substances’ bonding
they have strong covalent bonds within the molecules and only weak forces of attraction between molecules
Covalent molecular substances melting and boiling points
they have low melting and boiling points as only the weak forces between the molecules are broken when they change state
Covalent molecular substances’ conductivity
they don’t conduct electricity as they have no charged particles that are free to move
