B, As only are metalloids or have semimetallic properties.
Answer:The standard reduction potential, Eo , for Pb2+(aq) is greater than that for Mg2+(aq).
Explanation:
Metals are usually arranged in an order of reactivity called activity series. Metals that are high up in the series are good reducing agents with very low (very negative) reduction potentials. Metals with greater (less negative) reduction potentials are found lower in the series. In the image attached, elements were arranged according to their reducing ability. Magnesium is very electro positive hence it is a better reducing agent with a lesser standard reduction potential than lead(refer to the image for numerical values of standard reduction potentials). Hence it displaces lead from solution and the elemental lead deposits on the wire.
Use the ideal gas equation PV=nRT. You can compare before and after using P1V1/n1T1=P2V2/n2T2. Since the number of moles remains constant you can disregard moles from the equation and use pressure, volume and temp. Make sure your pressure is converted to atmospheres, your volume is in liters, and your temperature is in kelvins.
<span>3 elements
Nitrogen
Hydrogen
Oxygen
2 nitrogen 4 hydrogen and 3 oxygens
there are only 3 different elements</span>