Chemistry Yr 9 - Periodicity + Bonding Flashcards
Name the trends in Group 1?
Known as the Alkali Metals
Reactivity increases as you go down the group
metals
really reactive
melting + boiling point gets lower as you go down the group
Name the trends in group 7?
Known as the halogens
reactivity decreases as you go down the group
more reactive halogen will replace a less reactive halide
Highly reactive
non metals
Name trends in group 0?
known as the noble gases
unreactive
colourless and odourless
low melting points
non metals
non flammable
stable not needing to loose or gain electrons
Name similarities between group 1 and 7
highly reactive.
Both groups form ionic compounds
Their elements react with other groups to achieve a full outer shell of electrons.
What is ionic bonding?
the transfer of electrons between a metal and non-metal.
ionic bonds form between oppositely charged ions
what is covalent bonding
atoms are held together by sharing pairs of electrons between non metals
what is metallic bonding?
the electrostatic attraction between positive metal ions and a sea of delocalised electrons
name the physical properties in the halogens?
strong covalent bonds
weak intermolecular forces
low melting and boiling points
poor conductors of heat and electricity
Name the chemical properties of the halogens?
all have 7 electrons in their outer shell
they all want to gain one more electron to have a full outer shell either by ionically bonding or covalently bonding
Name the physical properties of group1
have very low density
very soft
can be cut with a knife and then goes dull as it oxidises
needs to be stores in oil to stop it reacting with the water ion the air
What did John Dalton contribute to the periodic table?
came up with the table of elements
elements where ordered by their atomic weights
What did John Newlands contribute to the periodic table?
the law of octaves but broke down after calcium
built on Daltons ideas and arranged the known elements by atomic mass
What did Dmitri Mendeleev contribute to the periodic table?
he arranged the elements according to atomic weight
he grouped elements with similar properties together
he left gaps for unknown elements and predicted what their properties would be when the elements where discovered they matched his predictions and his table was accepted by the scientific community
Properties of metals
shiny
mostly solid
dense and strong
good heat
good electrical conductors
properties of non metals
dull
low density
weak
brittle
poor heat
poor electrical conductor
why was the periodic table being developed?
chemists tried to classify the elements it arranges them in an order which is similar elements are grouped together
What are intermolecular forces?
they are weak forces if attractions between molecules influencing their physical properties like melting/boiling points and states of matter
in group 0 does the boiling point increase or decrease as you go down the group?
increases
What’s the modern name for atomic weight?
relative atomic mass
Why did Mendeleev reverse the order of tellurium and iodine?
he reversed them as his periodic table was also based on the elements properties not just their atomic weight.
Why did scientists reject Newlands ideas?
his law of octaves broke down after calcium
he put elements with different properties in the same group instead prioritising atomic weight
he didn’t leave gaps for unknown elements
why did scientists accept Mendeleev’s ideas?
he accurately placed elements by their chemical properties and atomic mass
he left gaps for undiscovered elements
his predictions of unknown elements where accurate so when those elements where discovered they had a place on the table
what happens when sodium reacts with chlorine?
produces bright yellow flame and releases heat
sodium loses one electron forming a positive ion and chlorine gains one electron forming a negative ion
this results in a stable ionic compound NaCl
in a modern periodic table how are elements ordered?
by atomic number
when anything is reacted with group one what gas is released?
hydrogen
What state is astatine at room temperature?
Solid
formula of astatine?
At2
in a modern periodic table the elements are arranged in order of blank
atomic number
what elements are often used as catalysts
transition metals
name two differences you would see between the reactions of potassium and lithium with water
potassium reacts much faster as it moves around on the surface
potassium reacts more violently as its lower down the goup
