Mocks Flashcards
Define the mass number of an atom
The total number of protons and neutrons in an atom
Mass number = proton number + neutron number
What is the equation to find relative atomic mass
Relative atomic mass=
(mass number of isotope 1 x percentage abundance of isotope 1) +
(mass of isotope 2 x percentage abundance of isotope 2)
Then divide by 100
What does the number 24 represent in 24
Mg
The mass number
Compare the differences between the plum pudding and the nuclear model of the atom
Plum pudding:
The atom is mostly positvely charged ‘dough’
Negative electrons are distributed throughout the atom
The mass of the atom is evenly distributed
Nuclear model:
The atom is mostly empty space
Negative electrons orbit the nucleus at a distance
Almost all of the mass of the atom is concentrated into the positively charged nucleus.
What is the relative mass of each of the subatomic particles
Proton = 1
Neutron = 1
Electron = very small
What is the name used to describe the block of elements in the middle of the periodic table
The transition metals
Suggest a reason for the name given to the transition metals
The metallic elements that serve as a bridge or “transition” between the two sides of the table
State 2 typical properties of a transition metal
Maleable
Dense
Hard
Conductors of electricity
High melting and boiling points
Compare the physical and chemical properties of the transition metals and the alkali metals
All of the alkali (group 1) metals form ions with a +1 charge whereas the transition metals can form ions with variable charges.
The transition metals are muchharder, strongeranddenser than the group 1 metals, which are very soft and light.
The transition metals have much higher boiling points than the alkali metals.
The alkali metals react with water, oxygen and halogens while the transition metals either react very slowly or do not react at all - an example of this is the reaction with oxygen.
A group 1 metal will tarnish in the presence of oxygen as a metal oxide is formed.
When cut with a knife, the shiny appearance of the metal disappears in seconds as it is covered by the dull metal oxide
Do transition metals form coloured compounds
Yes they do typically form coloured compounds
Silver nanoparticles are sometimes used in clothing to prevent odours.
Suggest why it is more economical to use nanoparticles of silver rather than coarse particles.
The surface area to volume ratio of nanoparticles is high. This means that smaller amounts of materials can be used for our desired purpose compared to using normal sized particles. This makes them cheaper and more efficient to use than larger particles.
What is one use of nanoparticles
Suntan lotion
How does the size of nano particles compare to normal sized particles
Nano particles are much smaller
How do you calculate surface area to volume ratio
Surface area to volume ratio = surface area/volume
