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Interference colors in the light reflected from a thin soap film ...

Evidently the mass of a deuterium atom is very nearly twice that of iH 1, while the mass of ... These particles, which we now know are the nuclei of helium atoms, are ... Assume it to be of copper, of density 8.8 gm/cm 3 Its volume is 47ro3/3 or 4.2 ... 30 (2) The force exerted by the sodium ion is + X qci~ 4-n-eo r 2 (3) The force ...

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The Physics of Subatomic Particles

this indicates an atomic diameter of about 3.4 x 10''' m for an argon atom, ... that is , its atomic number times the average mass of the proton and neutron. ... with experimental values, and so it was assumed that this was the reaction ... The accelerated electrons struck a nickel crystal at a normal to its ... Avogadro's constant. ND.

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Unit of Density - Density Definition, SI unit, Solved Examples

Questions 3: If you find a shiny rock, a carbon allotrope with a volume of 0.042 cm³ and a mass of 0.14 g, is it graphite or ...

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A substance's density is defined as its mass per unit volume. The density symbol that is most commonly used is \rho

\text{ Density }=\frac{\text{ mass }}{\text{ volume }}

Given that

Sodium atom average density \rho = ?

Size(Diameter) of the sodium atom D = 2.5 A^{^0}

Avogadro's number NA = 6.023 * 10^{23} atoms

Atomic mass of sodium = 23 g = 23* 10^{-3} kg

Density of the sodium in its crystalline state \rho_c= 970 kg m^3

Step 1: Calculating the volume of the sodium atom

Radius of the Sodium atom r = \frac{D}{2} = \frac{2.5}{2} = 1.25 A^{^0}

r = 1.25 * 10^{-10} m        \because \text{1 angstrom = } 10^{-10}

Volume sodium atom (sphere) = \frac{4}{3}\pi r^3

= \frac{4}{3}* 3.14 * (1.25 * 10^{-10})^3

= 8.1845 * 10^{-30} m^3   

Step 2: Mass of the sodium atom using the Avogadro's law

1 mole of the sodium contains 6.023 * 10^{23} atoms has a mass   23* 10^{-3} kg

Mass of one sodium atom  =  ?

Mass of sodium atom = \frac{23* 10^{-3}}{6.023 * 10^{23}}   

= 3.818 * 10^{-26} kg

Step 3:  Determine the sodium atom average density

\text{ sodium atom average density } = \frac{\text{ Mass of sodium atom }}{\text{ Volume sodium atom }}

= \frac{3.818 * 10^{-26}}{ 8.1845 * 10^{-30}}   

=4.67*10^3\ \ kg/m^3  

Solid sodium atom average density \rho_s=4.67*10^{\ 3\ }\ \ kg/m^3  

Given that, \rho_c= 970 kg m^3

Thus, in its crystalline form, the density of sodium and the density of solid sodium are not the same. Since atoms are packed tightly during the solid process. In the crystalline phase, therefore, the interatomic separation is very small.