Here's my best guess
the volume of the unit cell is (385*10^-12)^3=5.7066*10^-29 m^3
multiply by density to get mass
mass = (7 g/cm^3)*(100^3 cm^3 / 1^3 m^3) * 5.7066*10^-29 m^3= 3.99466*10^-22 g
covert to moles
3.99466*10^-22 g * 1 mol / 239.82 g = 1.6657 *10^-24 mol
convert to number of units
1.6657 *10^-24 mol * 6.23*10^23 units/mol = 1.04
385 pm = 3.85*10^(-8) cm
The volume of the unit cell is the cube of that, which is 5.71*10^(-23) cm^3. Since the ratio of mass to volume (i.e. the density) must be the same no matter what amount of TlCl you have, you can say:
7 = x/(5.71*10^(-23)), where x is the mass of the unit cell. Solving for x, you get 4*10^(-22) g.
The mass of a molecule of TlCl is 240 amu, which in grams is 4*10^(-22) g. The mass of the unit cell and the mass of a molecule of TlCl is the same. Therefore there is one formula unit of TlCl per unit cell.
The answer is D. To put it simply, all atom wished to become stable. The only way for that is to obtain an octet structure where the outermost shell would have 8 electrons, thus being full.
Answer: -
²²³Ra is the daughter nuclide produced when ²²⁷Th undergoes alpha decay
Explanation: -
When alpha decay occurs, the mass number of the parent decreases by 4 and the atomic number decreases by 2.
Mass number of ²²⁷Th =227
Atomic number of ²²⁷Th = 90
Mass number of daughter = 227 - 4 = 223
Atomic number of daughter = 90 - 2 = 88
88 is the atomic number of Ra Radium.
Thus the daughter is ²²³Ra
Answer:
Explanation:
From the periodic table, the element designated as Sn is tin. Sn is derieved from a latin name of the metal called Stanum
Selenium Se is a group 6 element. It belongs to the same group with oxygen, sulfur and tellurium. This substance has an atomic weight of 78.96g/mol
Oxygen is a group 6 element with an atomic mass of 16. The atomic mass is the number of protons in the nucleus of this atom.
thnxx for free point? ?????????
