This is an incomplete question, the given sketch is shown below.
Answer : The name of given unit cell is, FCC (face-centered cubic unit cell)
Explanation :
Unit cell : It is defined as the smallest 3-dimensional portion of a complete space lattice which when repeated over the and again in different directions produces the complete space lattice.
There are three types of unit cell.
- SCC (simple-centered cubic unit cell)
- BCC (body-centered cubic unit cell)
- FCC (face-centered cubic unit cell)
In SCC, the atoms are arranged at the corners.

The number of atoms of unit cell = Z = 1
In BCC, the atoms are arranged at the corners and the body center.

The number of atoms of unit cell = Z = 2
The given unit cell is, FCC because the atoms are arranged at the corners and the center of the 6 faces.

The number of atoms of unit cell = Z = 4
Thus, the name of given unit cell is, FCC (face-centered cubic unit cell)
Answer: It will take for the concentration of A to decrease from 0.900 M to 0.210 M is 28.75 s
Explanation:
Zero order reaction : A reaction is said to be of zero order if the rate is independent of the concentration of the reactants, that means the rate is directly proportional to the zeroth power of the concentration of the reactants.
Expression for the zero order kinetics:
![[A]=-kt+[A]_o](https://tex.z-dn.net/?f=%5BA%5D%3D-kt%2B%5BA%5D_o)
where [A] = concentration left after time t = 0.210 M
= initial concentration = 0.900 M
k= rate constant =
t = time for reaction = ?


Thus it will take for the concentration of A to decrease from 0.900 M to 0.210 M is 28.75 s
Alkali metals impart characteristic colours to the flame due to low ionisation enthalpy, when an alkali metal or its salt is heated in a flame, the valence electrons are excited to higher energy level.
Answer:
Energy level where all chemical reactions occur. The remaining electrons are 'core' electrons that do not react.
Explanation: