P4 Nuclear Equations (page 197) Flashcards
What do Nuclear Equations show?
Radioactive Decay. by using element symbols (see page 196).
Do Mass and Atomic Number have to balance?
Yes
How are Nuclear equations written?
in the form:
atom before decay»_space;>
atom after decay + radiation emitted.
What is the golden rule to remember with Nuclear Equations?
Tot total mass and atomic numbers must be equal on both sides.
Alpha Decay decreases what?
Then charge and Mass of the Nucleus ⁴
He
²
What are Alpha particles made up of?
two protons and two neutrons.
What happens when an atom emits an alpha particle?
its atomic number reduces by 2 and its mass number reduces by 4.
A proton is positively charged and a neutron is neutral why?
so the charge of the nucleus decreases.
In nuclear equations, an alpha particle can be written as what?
helium nucleus:
⁴
He
²
(see picture on page 197).
What is the nuclear equation for this decay?
238 U»_space;> 234Th + 4He
92 90 2
(see picture of equation on page 197).
238 »_space;» 234 + 4
92 »_space;» 90 + 2
When a nucleus decays by alpha or beta decay, what rays are sometimes released?
Gamma Rays.
Beta Decay increases the charge of what?
the Nucleus
0
e
-1
(see symbol on page 197).
When Beta decay occurs, what happens to a neutron?
a neutron in the nucleus turns into a proton, and releases a fast-moving electron (the beta particle).
What happens if the number of protons in the nucleus has increased by 1? Explain why
It increases the positive charge of the nucleus (the atomic number). Because the nucleus has lost a neutron and gained a proton during beta decay, and the mass of the nucleus doesnt change (protons and neutrons have the same mass).
How is a beta particle written as an nuclear equation?
0
e
-1
Carbon-14 »_space;>beta decay»>
»Nitrogen 14»_space;» B particle (see picture on page 197).
What would the nuclear equation for this decay be?
14 14 0
C »_space;> N + e
6 7 -1
14»_space;> 14 + 0
6 »_space;> 7 - 1
(see picture 2 on page 197).
In both alpha and beta emissions a new element will be formed, as the number of protons (atomic number) changes.
Gamma Rays Don’t change the charge or mass of what?
The Nucleus.
Gamma rays are a way of getting rid of what?
excess energy from a nucleus.
This means that there is no charge to the atomic mass or atomic number of the atom.
Why type of radiation is given off in this decay?
8 8
Li »_space;» Be + Radiation
3 4
(1 mark)
Beta particles (1 mark)
Write the nuclear equation for
219
Rn decaying to polonium (Po)
86
by emitting an alpha particle
(3 marks)
219 215 4
Rn »_space;> Po + He
86 84 2
(1 mark for correct layout, 1 mark for correct symbol for an alpha particle, 1 mark for total atomic and mass numbers being equal on both sides).
