Atomic Structure Flashcards
What is the Particle Theory of Matter?
The idea that all matter is made up of small particles
What is the arrangement of particles in a solid?
A regular pattern
What is the relative distance of particles in a solid?
Very close/tightly packed
What is the movement of particles in a solid?
Particles vibrate around a fixed point
What is the arrangement of particles in a liquid?
Random
What is the arrangement of particles in a gas?
Random
What is the relative distance of particles in a liquid?
Close
What is the relative distance of particles in a gas?
Far away from each other
Describe the movement of particles in a liquid
They move around each other
Describe the movement of particles in a gas
They move quickly in all directions
When particles are given more energy, how does their movement change?
They move quicker
What is the point that a solid changes into a liquid?
The melting point
What is the point in which liquid become a gas?
The boiling point
Describe the temperature when a substance changes state
Constant
Do bonds require energy to be broken?
Yes
Do bonds release energy when made?
Yes
Give 3 limitations of the particle model
It doesn’t take into account:
- size of particles
- forces of attraction
- space between particles
Can a gas be compressed? (How much if so?)
Yes - a lot
Can a liquid be compressed? (How much if so?)
No
Can a solid be compressed? (How much if so?)
No
What happens to the forces of attraction when a solid becomes a liquid?
Some of them are overcome
What happens to the forces of attraction when a liquid becomes a gas?
All of them are overcome
Do bonds break when substances change state
NO, only the forces of attraction are overcome
What kind of temperatures are needed for bonds to break?
Very high
What is an atom?
The smallest part of an element that retains the properties of that element
What is the radius of an average atom?
- 10
1 m
What is the mass of an average atom?
-23
10 g
Describe the structure of an atom
A central, positively charged nucleus surrounded by shells of negatively charged electrons
Describe the radius of the nucleus in comparison to the whole atom
Much smaller
What is the nucleus of an atom made up of?
Protons and neutrons
Why does an atom have an overall neutral charge
Because there are the same numbers of protons and electrons
What does the mass number of an element show?
The total number of protons and neutrons
What does the atomic number of an element show?
The number of protons in an atom (therefore number of electrons too)
What is an ion?
When an element loses or gains electrons
What is the atomic mass unit of a proton?
1
What is the Atomic mass unit (A.m.u) of a neutron?
1
What is the A.m.u of an electron
1/2000
What is the charge of a proton?
+1
What is the charge of a neutron?
0
What is the charge of an electron?
-1
What is an isotope?
Atoms of the same element with the same atomic number but different mass number (due to a different number of neutrons)
How many neutrons does a particle of Carbon-14 have? (Atomic number is 6)
8
How many electrons does the first shell have?
2
How many electrons do all other shells hold (for GCSE anyway)
8
What kind of evidence lead to changes in the particle model?
Experimental evidence
What year was Dalton’s model?
1803
What was Dalton’s conclusions about the particle model
Atoms can’t be broken down into anything simpler
Atoms of a given element are identical to each other
Atoms of different elements are different from each other
During chemical reactions atoms rearrange to make different substances
What did Dalton imagine atoms to be?
Tiny solid balls
What did J.J Thomson discover?
The electron
What model was developed by J.J Thomson?
The plum pudding model
What conclusions did J.J Thomson conclude about the atom?
Atoms are overall neutral
Atoms are spheres of positive charge with electrons dotted around inside
What year did J.J Thomson develop the plum pudding model?
1897
The Geiger - Marsden Experiment took place in which years?
1909-1911
How did Geiger and Marsden test the plum pudding model?
By firing positively charged particles at very thin gold foil
What model did Ernest Rutherford discover?
Planetary model
What year did Niels Bohr improve Rutherford’s model?
1913
How did Niels Bohr improve Rutherford’s model?
Discovered that electrons occupy shells or energy levels around the nucleus
What is a subatomic particle?
An object found in atoms (eg. Protons, neutrons and electrons
What does RAM stand for? (Ar)
Relative atomic mass
What does RMM stand for? (Mr)
Relative molecular mass
What is the RAM?
The ratio of the average mass of one atom of an element to a twelfth of the mass of an atom of carbon-12
What does RFM stand for? (Mr)
Relative formula mass
What is the empirical formula of C6H12O6?
CH2O
What is the empirical formula?
The simplest whole number ratio of each type of atom in a compound
How can the empirical formula be calculated?
From the number of atoms present or by converting the mass of the element/compound
What happens to the particles of a substance when it changes state?
The arrangement and movement of them change
When substances change state, how does their mass change?
It’s stays the same (conservation of mass)
How do you convert the mass of an element/compound to calculate the empirical formula?
Find the number of moles
Mass
RFM
