Turning Points in Chemistry Flashcards
When investigating the atom Dalton followed these steps. Place them in the correct order:
Test the explanation
Suggest a different explanation if needed
Check the evidence
Ask a question
Test and check the evidence again
Suggest an explanation
Ask a question Suggest an explanation Test the explanation Check the evidence Suggest a different explanation if needed Test and check the evidence again
What is the name of the tiny particles that make up everything
Atoms
Name the 3 subatomic particles in an atom
Electrons
Neutrons
Protons
What charge does a neutron have?
No charge (Neutral)
If an atom has 7 electrons how many protons does it have?
7 (no. of protons = no. of electrons)
Which subatomic particles are found in the nucleus?
Neutrons
Protons
In the gold foil experiment what did Rutherford ‘shoot’ at the gold foil
Positive alpha particles
Which sub atomic particle was discovered through the gold foil experiment
Proton
Why did the alpha particles bounce off the protons?
Like charges repel - Protons have positive charges
If the majority of alpha particles went through the foil what does that suggest about atoms
They are mainly empty . The nucleus is compact/small
What property was the first thing Mendeleev based the periodic table off
Atomic mass
Mendeleev grouped elements based off what?
Physical properties
Formula of its compounds with hydrogen and oxygen
Why did Mendeleev leave gaps in the periodic table
For elements he had been predicted but had not been discovered
Rhenium is a catalyst. What is a catalyst?
A catalyst is something that speeds up chemical reactions but remains unchanged after the reaction
What is a fossil?
Remains, traces or imprints of plants or animals
Which rock type do fossils occur in
Sedimentary
How is a fossil formed
Death and burial by sediments.
The fleshy parts rot away/dissolved/ are broken down by bacteria.
Rock forms around the skeleton and minerals replace the original skeleton forming a hard copy.
Rock around the fossil erodes and exposes the fossil.
Why does fossils not form in igneous or metamorphic rock
magma, lava, heat and pressure would destroy remains
Layers of sedimentary rock are called what?
Strata
What is an index fossil
A fossil with a known age that can be used to identify the age of the strata
Why were the cathode rays deflected in Thompson’s experiment?
Cathode rays have a negative charge. Electrons in the atom have a negative charge so deflected the rays as like charges repel
What was the name of Thompson’s model of the atom
plum pudding model
Why is it so important to the scientific community that scientists write their findings up in scientific journals?
so that they can check the results/ carry out the investigation themselves
allows repeats to be carried out many times, providing more accurate/ reliable results
allows scientific knowledge to develop/ other scientists may use the results to carry out new investigations
How can the location of a fossil give an indication of its age?
Fossils are found in distinct layers/ strata of rock.
Different strata have different ages/ different strata correspond to different time periods/ lowest strata were formed earlier/ fossils in lower strata are older.
Only certain fossils are found in certain strata or time periods/ index fossils give the age of the strata and nearby fossils.
Dalton suggested that there was space between particles. Think of an example that proves this.
Salt in water experiment. The water does not overflow when salt is added. If there was no space then the water would overflow straight away
A syringe containing air can be compressed.
The space is reduced when the particles are pushed together.
If there was no space it would not be able to be compressed
Which subatomic particle is the smallest?
Electron
