Among $10^{-9}$ g (each) of the following elements, which one will have the highest number of atoms? Element: Pb, Po, Pr and Pt
Pr
Atom Count and Molar Mass Relation
The number of atoms in a given mass of a substance depends on its molar mass. For a fixed mass, the element with the lowest molar mass will contain the highest number of atoms.
The number of atoms can be calculated using the formula:
$ \text{Number of atoms} = \frac{\text{Mass}}{\text{Molar Mass}} \times N_A $
Where \( N_A \) is Avogadro's number. Since the mass (\( 10^{-9} \) g) and \( N_A \) are constant for all elements in this question, we only need to compare their molar masses to determine which has the most atoms.
Element Molar Mass Data
| Element | Symbol | Molar Mass (g/mol) |
|---|---|---|
| Lead | Pb | 207.2 |
| Polonium | Po | 209 |
| Praseodymium | Pr | 140.9 |
| Platinum | Pt | 195.1 |
Highest Atom Count Determination
By comparing the molar masses from the table:
- Pb: 207.2 g/mol
- Po: 209 g/mol
- Pr: 140.9 g/mol
- Pt: 195.1 g/mol
Praseodymium (Pr) has the lowest molar mass (140.9 g/mol). Consequently, \( 10^{-9} \) g of Pr contains the highest number of atoms compared to the same mass of Pb, Po, or Pt.
Similar Questions
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Important Questions from Physical Chemistry
$CaCO_3(s) + 2HCl(aq) \rightarrow CaCl_2(aq) + CO_2(g) + H_2O(l)$
Consider the above reaction, what mass of $CaCl_2$ will be formed if 250 mL of 0.76 M HCl reacts with 1000 g of $CaCO_3$ ?
(Given: Molar mass of Ca, C, O, H and Cl are 40, 12, 16, 1 and 35.5 g $mol^{-1}$, respectively)- According to Bohr's model of hydrogen atom, which of the following statement is incorrect?
Two vessels A and B are connected via stopcock. The vessel A is filled with a gas at a certain pressure. The entire assembly is immersed in water and is allowed to come to thermal equilibrium with water. After opening the stopcock the gas from vessel A expands into vessel B and no change in temperature is observed in the thermometer. Which of the following statement is true ?Which of the following graphs correctly represents the plot of $K_H$ at 1 bar for gases in water versus temperature?
If equal volumes of $AB_2$ and $XY$ (both are salts) aqueous solutions are mixed, which of the following combination will give a precipitate of $AY_2$ at 300 K ?
(Given $K_{sp}$ (at 300 K) for $AY_2=5.2 \times 10^{-7}$)
