Flashcards in Chapter 1- Matter and Radiation Deck (39)
What is the charge of the nucleus?
What surrounds the nucleus of an atom?
Negatively charged particles called electrons
What is the nucleus comprised of?
Positive protons and neutral neutrons that have approximately the same mass
What can you infer about an uncharged atom ?
That it has equal amounts of protons and electrons.
Why do radioactive substances emit radiation?
The nuclei of their atoms are unstable
What can happen when radioactive substances pass through other substances?
It can ionise them.
What are the three types of radiation from radioactive substances?
Alpha, beta and gamma
Which radiation is the most ionising?
Which radiation is the most penetrating?
What can stop alpha radiation?
A piece of paper
What can stop beta radiation?
2-3mm of metal
What is the half life of a substance?
The time it takes for the number of atoms of that substance to decrease by half.
What is a nucleon?
A proton or neutron found in the nucleus.
What do we know about atoms from Rutherford's alpha scattering investigations?
Every atom contains:
A positively charged nucleus composed of protons and neutrons
Electrons that surround the nucleus
The nucleus contains most of the mass of the atom but occupies 0.000,01 times the diameter of the atom.
What holds the electrons in the atom?
Electrostatic force between the negatively charged electrons and the positively charged nucleus.
What do you notice about the mass of subatomic particles?
The electron has a much smaller mass than both the proton and the neutron.
The protons and neutron have almost equal mass.
What do you notice about the charges of the subatomic particles?
The electron has equal and opposite charge to the proton. The neutron is uncharged.
What is the same about all atoms of a given element?
They all have the same number of protons.
What can be different about atoms of a given element?
They can have different numbers if neutrons.
Define an isotope.
Atoms with the same number of protons but different numbers of neutrons.
What is the nucleon number?
This is sometimes called the mass number.
The total number of protons and neutrons in an atom.
What is a nuclide?
Each type of nucleus labelled using isotope notation.
What is the specific charge of a charged particle?
It's charge divided by its mass.
What particle has the highest specific charge?
What part of the atom has zero charge?
What part of the atom has the largest specific charge?
What part of the atom leaves a different isotope of an element when it is removed.
What is the strong nuclear force?
The force that overcomes the electrostatic force of repulsion between the protons in the nucleus, keeping the protons and neutrons together.
What is the range of the strong nuclear force?
No more than 3-4 centimetres