Level 3 is the correct answer
Answer:
Δm = 3.0684
Explanation:
Data Given:
Atomic number of lithium = 3
Atomic mass of lithium = 7.0144 amu
Mass of 1 proton = 1.0073 amu
Mass of 1 neutron = 1.0087 amu
Solution:
Mass Defect:
Mass defect is the difference of mass number of an atom and its atomic number.
Formula used
Δm = [Z (mass of proton + mass of nutron) + ( A − Z ) mass of nutron] − m of atom
where:
Δm = mass defect (amu)
Z = atomic number
A = mass number
Put values in formula
Δm = [3 ( 1.0073 amu + 1.0087 amu) + ( 7 − 3 ) 1.0087 ] − 7.0144
Δm = [3 (2.016) + (4) 1.0087 ] − 7.0144
Δm = [(6.048) + (4.0348) ] − 7.0144
Δm = 10.0828 − 7.0144
Δm = 3.0684
<h3>Answer:</h3>
Option-D, "their elements have very similar properties and exhibit a clear trend" is the correct answer.
<h3>Explanation:</h3>
In periodic table the elements are arranged in tabular form with respect to their atomic masses, atomic numbers, electronic configurations and chemical properties. It is called periodic because the properties of elements repeats periodically.
Furthermore, the rows from left to right also called Periods basically shows the metallic and non metallic characters of elements. \those on the left are metals and those at the rights are non metals.
The columns from top to bottom are called as Groups. Groups contain elements of same chemical properties.
<h3>Example:</h3>
Group I elements are called as <em>Alkali Metals</em>. They all have one valence electron and hence, loose one electron to form the corresponding cation. i.e.
M → M⁺¹ + 1 e⁻
Group VII elements are called <em>Halogens</em>, they all are non metals and tend to gain one electron to form the corresponding halide ion. i.e.
X + 1 e⁻ → X⁻¹
Answer:
Explanation:
When determining empirical formulas of hydrates we have to find the mass of water which left the hydrate when heating The sample. This amount of water calculated will provide us with the correct ratio of moles water / moles anhydrate since moles water > moles anhydrate. The mistake might have been done while determining the water that left the sample so then we see and impropre result in ratios.
The frequency and energy of most energetic of these photons is
Hz and 
J respectively.
The high energy photons will have least wavelength. Taking the given less wavelength for calculation of frequency and energy of photons.
λ = 2200 Å
Also, we know, 1 Å = 
m
So, λ = 
λ = 
<em> </em>m
Now, calculating frequency using the formula -
c = fλ, where c is speed of light, f is frequency and λ is wavelength.
We know, c = 
m/s
f = c/λ
f = 
frequency = Hz
Now, calculating Energy through the formula -
E = hf, where E is energy, h is planck's constant and f is frequency
Value of planck's constant = 
Js
E = *
Energy = J
Thus, frequency and energy of photons is Hz and J respectively.
Learn more about energy of photon -
brainly.com/question/15946945
#SPJ4
