Flashcards in Periodicity Deck (50)
What bonds are covalent
what is monoatomic
noble gases that don't bond
how is the elements in the periodic arranged?
increasing proton number but took into account similar properties
What does high values of periodicity indicate?
a lot of energy is needed to separate the particles
what are intermolecular bonds?
bonds between two atoms
what are intramolecular bonds?
bonds inside an atom
what type of bonds are between noble gases?
why do carbon and silicon have a high melting value?
they are covalent networks and have a strong attraction as they want to gain 4 electrons
why is the size of an atom very difficult to measure?
it doesn't have a distinct edge
how is the bond length measured?
the nuclei of an atom to the nuclei of the other atom
what is the covalent radius?
half the distance between the nuclei of two of its
covalently bonded atoms.
what happens to the atomic size going along a period?
as it goes along a period the atomic size decrease as the nuclear charge is stronger so it pushes the electrons closer together
what happens to the atomic size going down a group?
the atomic size increases as it has an extra outer energy level of the occupied shells and the electrons to the nucleus is further apart.
what is the screening effect?
there is more outer shell between the nucleus and electrons so there is less attraction
why do noble gas don't have a covalent radius?
They don't have bonds as they are stable
What is ionisation energy?
the energy required to remove one mole of electrons from one mole of gaseous atoms
As you go along a period what happens to the ionisation number?
the nuclear charge between the protons and electrons are stronger and more attraction so the ionisation number increases
As you go down a group what happens to the ionisation energies?
The ionisation energy decreases as the electrons ,are further apart from the nucleus therefore the attraction isn't as strong (screening effect)
What is electronegativity?
Measure of an atom's attraction for the shared pair of electrons in a bond
What happens to the electronegativity as you go across a period?
It increases as it has more protons which is because it has an increase in nuclear charge
What happens to the electronegativity as you go down a group?
the electrons are further apart from the protons so the attraction isn't as strong as there is more outer shells.
The screening effect prevents the electrons to nucleus so attraction isn't as attraction
What is a covalent bond?
the attraction between the positive nucleus and the delocalised electrons
why can graphite conduct electricity?
because it has a delocalised electron as it only forms 3 bonds so has one bond left
what elements in the first 20 have a covalent network substance?
Boron, carbon and silicon
why can diamond not carry out electricity?
because it forms 4 bonds with carbon atoms so it has no delocalised electrons
why is diamond the hardest natural substance?
because it has 4 strong bonds
why is graphite soft and flaky?
It has weak bonds and is in layers
what is a use of diamond?
the tip of drill contains diamond to cut through glass or tiles
Why is graphite used as an industrial lubricant?
It has layers so it is easy to move the weak bond s