Polonium, the period 6 member of group 6a(16), is a rare radioactive metal that is the only element with a crystal structure based on the simple cubic unit cell. if its density is 9.232 g/cm3, calculate an approximate atomic radius for polonium―209.

Approximate atomic radius for polonium-209 is 167.5 pm .

Explanation:

Number of atom in simple cubic unit cell = Z = 1

Density of platinum =

Edge length of cubic unit cell= a = ?

Atomic mass of Po (M) = 209 g/mol

Formula used :  

where,

ρ = density

Z = number of atom in unit cell

M = atomic mass

= Avogadro's number  

a = edge length of unit cell

On substituting all the given values , we will get the value of 'a'.

Atomic radius of the polonium in unit cell = r

r = 0.5a

Approximate atomic radius for polonium-209 is 167.5 pm.

the answer is b

explanation:

the simple machine has three main features. they are:

fulcrum is the center point or pivot point of the machine. effort is input force/ applied force. load is external force/ output.

the keisha 's machine labels are

x : load

y: fulcrum

z: lever