Answer: half life
Explanation: Radioactive decay follows first order kinetics and the time required for the decay of a radioactive material is calculated as follows:

t= time required
k= disintegration constant
x= amount of substance left after time t
a= initial amount of substance
when one half of the sample is decayed, one half of the sample remains and t can be represented as 
at
, 


Atomic mass. Which is the number of protons and neutrons combined.
Answer:
Option 1
Explanation:
Option number 1 is the most compact one which indicates it is a solid
A form of
electricity which can attract things is static electricity. Static electricity
is the result of an imbalance between negative and positive charges in an
object. These charges built up o the surface of an object until they find a way
to e released or discharged causing the attraction of things.
Solid - made up of tightly packed particles, which gives it a solid shape.
Gas - made up of very loose particles, giving it more freedom to roam around as a gas
Liquid - fills into whatever it gets put in, basically takes the shape of the object its in