Answer: 226 Subscript 88 Baseline Upper R a right arrow Superscript 222 Subscript 86 Baseline Upper R n + Superscript 4 Subscript 2 Baseline Upper H e
Explanation:
Alpha decay : When a larger nuclei decays into smaller nuclei by releasing alpha particle. In this process, the mass number and atomic number is reduced by 4 and 2 units respectively.
The general representation of alpha decay reaction is:

Representation of Radium decays to form Radon

Thus 226 Subscript 88 Baseline Upper R a right arrow Superscript 222 Subscript 86 Baseline Upper R n + Superscript 4 Subscript 2 Baseline Upper H e represents alpha decay.
Answer:Trials are repetitions of the same procedure. These are done for a couple of reasons: To minimize the impacts of errors done in any one trial by averaging multiple trials together. To minimize random effects and the effects of uncontrolled variables by averaging multiple trials together.
Explanation:
Smashing a rock is not chemical tgats your answer
Answer: D. like dissolves like
Explanation:
The solubility of substances is governed by: Like dissolves like, which states that polar compounds are soluble in polar solvents and non polar compounds are soluble in non polar solvents.
Hydrocarbons are non polar in nature due to less difference between the electronegativities of carbon and hydrogen and thus are soluble in non polar solvents only.
Ionic compounds which are formed by elements with high electronegativity difference are polar in nature and thus dissolve in polar solvents.
Example:
in water.