Particles and atomic structure Flashcards
Describe the difference between a chemical and physical change
Physical- no new substance is made (change in appearance) te change can be reversed
Chemical- new substance is formed (change in appearance and energy) the change cannot be reversed
Outline the main properties of solids
High density (particles are packed together)
Cannot be compressed (no space between particles
Fixed shape
Cannot diffuse (particles can’t move)
Does not exert pressure on surrounding objects
Outline the main properties of liquids
Fairly high density
Cannot be compressed (hardly any space between particles)
No fixed shape (particles are free to move)
Can diffuse
Can exert small amounts of pressure on surrounding objects (particles are free to move)
Outline the main properties of gases
Low density (particles are far apart)
Can be compressed (large amount of space between particles)
Can diffuse
Can exert a lot of pressure (particles have alot of energy and move rapidly)
Limitations of the particle model
Does not show space between particles
Presents them as inelastic spheres which is not how they look
Does not show energy in particles
Does not show electrons
Why does the particle model not explain why atoms react with other atoms
During a chemical reaction it is the electrons that are involved and bond. The particle model does not show these electrons and therefore does not explain bonding.
Describe the structure of an atom
Th eatom consists of a positively charged nucleus (made from neutral neutrons an dpositive protons) surrounded by shells of negatively charged electrons. The nucleus radius is far smaller than the atomic rdaius and most of the atom is made from empty space
What is the size of a regular atom
10^-10m or 0.1nm
What are the realtive masses of protons neutrons and electrons
Protons- 1
Neutrons- 1
Electrons- 1/2000
What is the atomic charge
Number of protons (number of electrons)
what is the Mass number
The number of proptons + the number of neutrons
Why do atom sas a whole have no electrical charge
Because the 1+ protons cancel out the 1- electrons
What are Isotopes
The same atom but with adifferent amount of neutrons- the mass of the element is affected but not the charge.
They ahve the same chemical properties but their physical properties may differ.
How would you name a metal reacting with a non-metal
Name of metal first
Change end of non-metal to ide
How would you name a metal reacting with more than one element
Name of metal first
change name of non-metal to ate
