Answer: 
Explanation:
Alpha Decay: In this process, a heavier nuclei decays into lighter nuclei by releasing alpha particle. The mass number is reduced by 4 units and atomic number is reduced by 2 units.
General representation of an element is given as:
where,
Z represents Atomic number
A represents Mass number
X represents the symbol of an element
General representation of alpha decay :
The balanced nuclear equation when the isotope Strontium-90 decays by Q- decay is :

Answer:
im not smart but here
Explanation:
The strength of the gravitational force between two objects depends on two factors, mass and distance. the force of gravity the masses exert on each other. If one of the masses is doubled, the force of gravity between the objects is doubled. increases, the force of gravity decreases.
The maximum number of electrons:
- s sublevel: 2 electrons,
- p sublevel: 6 electrons,
- d sublevel: 10 electrons,
- f sublevel : 14 electrons.
Answer:
Explanation:
i think the anwer would be that its elliptical orbit and the tilt an its axis.