Half term 1 Flashcards
What are group one elements also called?
alkali metals
What are the main properties of group 1 elements?
soft
low densities
low melting and boiling points
very reactive
What group are alkali metals in?
group 1
What are the trends as you move down group 1?
Increasing reactivity
decreasing mpt and bpt
higher relative atomic masses
Why does the reactivity increase as you move down group 1?
outer electron more easily lost
attraction between the nucleus and the electron decreases because the electron id further away from the nucleus due to there being more shells
What ions do alkali metals make?
1+
Why is it so easy for alkali metals to form ions?
They only need to lose one electron to get a full outer shell and that does not take much energy
What are the ionic compounds formed by alkali metals usually like?
white solids
dissolve in water to form colourless solutions
Why do alkali metals only ever react to form ionic compounds>
It is so easy for them to lose their outer electron.
How do alkali metals react with water?
They react vigorously to form products hydrogen gas and metal hydroxide:
compounds that can dissolve in water to produce alkaline solutions.
More reactive metals result in a more ….. reaction?
violent/ vigorous
the amount of energy given off will also increase
How do alkali metals react with chlorine?
react vigorously when heated with chlorine gas to produce white metal chloride salts
How do alkali metals react with oxygen?
forms a metal oxide (the type of oxide depends on the alkali metal reacted)
Why do transition metals tarnish in the air?
They react with oxygen in the air which causes a dull metal oxide layer to form
Lithium reacts with oxygen to form ….
lithium oxide
Sodium reacts with oxygen to form….
a mixture of sodium oxide and sodium peroxide
Potassium reacts with oxygen to form….
a mixture of potassium peroxide and potassium superoxide
How are alkali metals different to transition metals?
alkali metals are much more reactive, less dense, less strong, less hard and have lower melting points.
How are the particles in solids arranged?
strong forces of attraction between particles- holds them close together in a regular lattice arrangement
particles vibrate around a fixed point
keep a definite shape and volume
expand slightly when heated - the particles vibrate more
How are the particles in liquids arranged?
Weak forces of attraction between particles
randomly arranged and free to move past each other- tend to stick closely together.
definite volume
no definite shape- flow to fill the bottom of a container
particles constantly move in a random motion
expand slightly when heated - the particles move around more
How are the particles in gases arranged?
very weak forces of attraction between particles
free to move and are apart - particle in gases travel in straight lines
no definite shape or volume - fills the container
particles move constantly in a random motion
particles move faster when heated - gas either expands or has an increase in pressure
What factor controls that state a substance is at a certain temperature?
how strong the forces of attraction are between the particles
The strength of the forces of attraction between particles depends on three things?
temperature
pressure
the material
What are the drawbacks of particle theory?
particles aren’t solid, inelastic or spheres - they are atoms ions or molecules
model doesn’t show forces between the particle - no way of knowing how strong they are
What does a change of state change about the particles?
their arrangement or energy
solid to liquid?
melting
Liquid to solid?
freezing / solidifying
Liquid to gas?
evaporating
gas to liquid?
condensing
gas to solid?
deposition
solid to gas?
sublimation
The boiling point is where…
a liquid changes to a gas
the melting point is where…
the solid changes to a liquid
What are the 3 types of bonding?
Covalent
Ionic
Metallic
Covalent bonding is where…
atoms share electrons so they have full outer shells
Each single covalent bond provides…
one electron for each atom
Covalent bonding happens in both…
compound (H20) and elements (Cl2)
What three ways can you draw covalent bonds?
Dot and cross diagrams
structural formulae (displayed formula)
Three dimensional structures
Does ionic bonding happen between metals or non metals?
metal - non-metal
What happens in ionic bonding?
transfer of electrons
metal atom loses electrons to form positively charged ion
non metal gains these electrons to form a negative ion
They are strongly attracted to one another by electrostatic forces, this is an ionic bond
What is the name of the forces holding ionic compounds together?
electrostatic forces
What is metallic bonding?
where a sea of delocalised electrons hold together positive ions
Is metallic bonding strong?
It is very strong
What are some key properties of metals?
solid at room temperature
conduct electricity and heat
most are malleable
What are alloys?
Metals that are mixed with other metals (or sometime non-metals) to make them stronger, better suited for a job
the different sized atoms distort the layers and make it difficult for the atoms to slide over each other- making the metal harder
Physical properties of metals:
strong(hard to break)
malleable
great conductors of heat and electricity
high mpts and bpts
lustrous (shiny)
sonorous (ringing sound when hit)
Physical properties of non metals
dull looking
more brittle
low mpts and bpts generally
often lower densities
mostly don’t conduct
Why can non metals have a range of different chemical properties?
They can form a variety of different structures
What are elements made up of?
atoms with the same atomic number
What subatomic particle determines the type of atom?
proton
What are isotopes?
different forms of the same element
same number of protons
different number of neutrons
What is a molecule?
two or more atoms held together by chemical bonds (can have different atoms)
What is a compound?
two or more different elements held together by chemical bonds
What is a mixture?
two or more substances that are not chemically combined
What are 3 conclusions drawn from the alpha scattering experiments?
- Most of the atom was empty space.
2.There is a concentrated area of positive charge in the atom.
3.Atoms contain a very small, heavy mass.
Who discovered the electron?
J. J Thompson
Who discovered the proton?
Ernest Rutherford
Who discovered the neutron?
James Chadwick
When was the proton discovered?
1917
When was the electron discovered?
1897
When was the neutron discovered?
1932
Where does the word ‘atom’ come from?
The Greek word ‘atomos’ meaning indivisible
Who described atoms as solid spheres?
John Dalton
Who created the plum pudding model?
J.J.Thompson
Who created the first nuclear model?
Ernest Rutherford
Who conducted the alpha particle scattering experiments?
Ernest Rutherford
Hans Geiger
Ernest Marsden
What was different about Niels Bohr’s nuclear model?
He had the electrons on shells orbiting the nucleus at fixed distances from it.
if there was a cloud of electrons they would all be attracted to the nucleus and the atom would collapse
What is the structure of a ionic compound like?
a giant ionic lattice
closely packed regular lattice arrangement
What are the forces like in ionic compounds?
very strong electrostatic forces of attraction between oppositely charged ions in all directions of the lattice.
What are the properties of ionic compounds?
High melting and boiling points
Conduct electricity when they are molten or dissolved - the ions are free to move and carry electrical charge
Atoms are stable when they…
have full outer shells
How do you work out the number of neutrons in an atom?
mass number - atomic number
Proton relative mass?
1
Proton relative charge?
+1
Neutron relative mass?
1
Neutron relative charge?
0
Electron relative mass?
0 (negligible)
Electron relative charge?
-1
What is the overall charge of an atom?
no overall charge
Group 0 elements are also known as…
noble gases
Properties of the noble gases?
Exist as monatomic gases-single atoms not bonded to each other
practically inert (unreactive)
non-flammable
colourless at room temp
As you move down the noble gases they:
increasing atomic mass
increasing boiling point - caused by greater intermolecular forces which need to be overcome.
What used to be the two clear ways to categorize elements?
Their physical and chemical properties
their atomic weight
How were elements originally organised?
by their atomic weight
they didn’t take into account the properties
When did Dmitri Mendeleev publish his periodic table?
1869
What was different about Mendeleev’s periodic table?
He left gaps for unknown elements
showed elements with the same chemical properties lined up in groups
Group 7 elements are also called …
Halogens
As you move down the halogens they:
become less reactive
have higher melting and boiling points
have higher relative atomic masses
What is the order of the reactivity series?
potassium
sodium
lithium
calcium
Magnesium
carnon
zinc
iron
tin
hydrogen
copper
What is an example of a group 1 element reacting with chlorine?
sodium + chlorine -> sodium chloride
What is a macromolecule?
A giant covalent structures
bonds arranged in giant lattices or networks
small molecules contain …
a fixed number of atoms joined by covalent molecules
giant covalent structures contain …
many atoms joined by covalent bonds
Potassium
sodium
calcium
