What are the 4 steps of the scientific process?
-Question – make an observation
-Answer, by forming theory or model
Where do scientists publish their work?
What do scientific journals contain?
How are scientific journals judged before they are published?
How can scientists make sure scientific journals are of good standard?
-If the experiments can be reproduced
What does testing a theory entail?
-Repeating exact experiments
-Using theory to make new predictions, and then testing them with new experiments
Which 3 factors can influence the decision about science?
What is the generic term for protons and neutrons?
What is the charge and relative mass of a proton?
-+1 and 1
What is the charge and relative mass of a neutron?
-0 and 1
What is the charge and relative mass of an electron?
--1 and 1/2000
How big is each atom ≈ in diameter?
-1 × 10-10 m (0.1 nanometres)
How big is the nucleus compared to the atom?
-10,000 times smaller
What is most of the atom made of?
What defines an element?
What is another name for the proton number?
-Atomic Number (Z)
In a ******* atom, the number of electrons equals the number of protons.
What do the number of electrons cause in an atom?
-Reactions and chemical behaviour
What is the symbol for nucleon number?
What is the nucleon number basically the same as? Why?
-Electron mass is negligible
What is the name given to the visual representation of sub atomic particles in an atom and nucleus?
What is an isotope?
-Atoms with the same number of protons but different numbers of neutrons.
What are the 2 other isotopes of hydrogen?
-Deuterium and Tritium
How many neutrons does the normal hydrogen have?
How many neutrons does deuterium have?
How many neutrons does tritium have?
Why is hydrogen not changing as an atom, when neutrons are added?
-Changing number of neutrons does not affect the atom’s chemical properties.
How does the neutron number affect the atom?
-Affects the stability of the nucleus.
In general the greater the number of neutrons compared with the number of protons, the more u******* the nucleus.
What is the name given to most unstable nuclei? What do they do to become stable?
The s***** nuclear force binds n******* together.
Which two other forces act on nucleons in the nucleus?
What would happen if these (above) were the only forces acting in the nucleus?
-Nucleons would fly apart
Why would the nucleons fly apart despite gravity acting towards the centre?
-Gravitational force is so small, you can just ignore it