Which of the following elements of elements will dissolve in water to give a solution of high pH?

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7. Identify the particle X in the following nuclear reaction: $_{92}^{234}U \rightarrow _{90}^{230}Th + X$.

• Step 1: Apply the conservation of mass number (superscript) and atomic number (subscript). For mass number: $234 = 230 + \text{mass of X} \Rightarrow \text{mass of X} = 4$. For atomic number: $92 = 90 + \text{atomic number of X} \Rightarrow \text{atomic number of X} = 2$.
• Step 2: Identify the particle with a mass number of