The atomic radius is a measure of the size of an atom. The atomic radius is defined as one-half the distance between the nuclei of two identical atoms that are bonded together.
r is atomic radius of an atom and d is distance between the nuclei of two identical atoms
Atomic radius is dependent on the type of bond present. Types of bonds can be grouped as five descriptive types.
<span>Ionic bondsCovalent bondsMetallic bondsvan der Waals bondsHydrogen bonds</span>
Units used to measure atomic radius:
<span><span>Angstroms (Å): This the most common unit used. Equivalent to 1.0 x 10-10 meters.</span><span>Nanometer (nm): Equivalent to 1.0 x 10-9 meters.</span><span>Picometer (pm): Equivalent to 1.0 x 10-12 meters.</span></span>
Period Trends
As you move left-to-right across a period, in general (not including the noble gases), atomic radius decreases.
As you go left-to-right across a period, electrons are added to the same energy level. At the same time, protons are being added to the nucleus increasing positive charge in the nucleus. Increased positive charge in the nucleus pulls the electrons closer to the nucleus resulting in a smaller atomic radius.
Group Trends
As you move down a group, in general, atomic radius increases.
As you move down a group the number of electrons increases, thus increasesing the number of energy levels. The outermost orbital increases in size when you move down the group making the atom larger. Therefore, the atomic radius increases as the group and energy levels increase.
Answer : The atomic radius for Ti is, 
Explanation :
Atomic weight = 47.87 g/mole
Avogadro's number 
First we have to calculate the volume of HCP crystal structure.
Formula used :
.............(1)
where,
= density = 
Z = number of atom in unit cell (for HCP = 6)
M = atomic mass = 47.87 g/mole
= Avogadro's number
V = volume of HCP crystal structure = ?
Now put all the values in above formula (1), we get


Now we have to calculate the atomic radius for Ti.
Formula used :

Given:
c/a ratio = 1.669 that means, c = 1.669 a
Now put (c = 1.669 a) and (a = 2R) in this formula, we get:



Now put all the given values in this formula, we get:


Therefore, the atomic radius for Ti is, 
a) (NH4)2SO4 --- 1 mole of it contains 2 moles of N, 8 moles of H, 1 mole of S, and 4 moles of O.
MM = (2 moles N x 14.0 g/mole) + (8 moles H x 1.01 g/mole) + (1 mole S x 32.1 g/mole) + (4 moles O x 16.0 g/mole) = 132 g/mole.
6.60 g (NH4)2SO4 x (1 mole (NH4)2SO4 / 132 g (NH4)2SO4) = 0.0500 moles (NH4)2SO4
b) The molar mass for Ca(OH)2 = 74.0 g/mole, calculated like (NH4)2SO4 above.
4.5 kg Ca(OH)2 x (1000 g / 1 kg) x (1 mole Ca(OH)2 / 74.0 g Ca(OH)2) = 60.8 moles Ca(OH)2
0 K in Celsius scale is -273 degree Celsius and in Fahrenheit scale 459 degree F.
The degree of a body's heat or cold is referred to as the gas's temperature. It is stated in temperature units such as, degree Celsius, Fahrenheit and Kelvin these temperature units are interchangeable. To convert Celsius to Fahrenheit ° F = 9/5 ( ° C) + 32, kelvin to Fahrenheit= ° F = 9/5 (K - 273) + 32, Celsius to kelvin K = ° C + 273. to convert Fahrenheit to Celsius ° C = 5/9 (° F - 32) In this question, to convert Fahrenheit to Celsius ° C = 5/9 (° F - 32) = 0-273 K (5/9 - F-32) =459 degree F. and kelvin to Celsius K - 273 = C = -273 degree Celsius
At 8^0C K= 8 + 273 =281 degree Celsius and at 8F , 8= 9/5(k-273) +32 =453 F
To learn more about Fahrenheit and Celsius:
brainly.com/question/1844449
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