Answer:
a) 
b) 
c) 
d) 
Explanation:
For neutral atoms:
Atomic Number (Z)= number of protons = number of electrons
Mass number (A) = number of protons + number of neutrons
For ions with positive net charge:
Number of protons = Z + net charge
For ions with negative net charge:
Number of protons= Z - net charge
a) A = 71, Charge = +3
Number of electrons = 28
Number of protons = 28 +3 =31
b) A = 35, Z = 45+35=80, Charge = -1
Number of protons =35
Number of neutrons = 45
Number of electrons = 36
Charge = Number of protons- Number of electrons =35-36 = -1
c) Charge = +4
Number of electrons = 86
Number of protons = Z = 86+4 = 90
mass number = A = 90+142 = 232
d) Charge = +2
Atomic number = Number of protons = Z = 38
mass number = A = 87
Answer:
It is called liquid gold because of its high price and value and its economic need by all the countries worldwide.
Explanation:
Petroleum is present in abundant quantity in the some regions . So it is considered as Liquid gold, which they value a lot.
Divide this problem in to two steps: 1. Convert millimoles to moles. 2. Convert moles to grams.
1.
2.65 mlmol x 1mol/1000mlmol=.00265mol
2.
.00265mol x 32.065g/1 mol=.0850g S
Let me know if you need more explanation on why I used the conversions that I did.
Answer:
241 nm, it is UV light range
Explanation:
The minimum energy needed required to break the oxygen-oxygen bond = 495 kJ/mol
Energy needed for 1 molecule of oxygen = 495 × 10³ J / avogadro's constant = 495 × 10³ J / ( 6.02 × 10²³) = 8.223 × 10⁻¹⁹ J
Energy = hv
where h = Planck constant = 6.626 × 10 ⁻³⁴ m²kg/s and v = frequency
c speed of light = vλ
c / λ = v
E = hc / λ
λ = hc / E = (6.626 × 10 ⁻³⁴ m²kg/s × 3.0 × 10 ⁸ m/s) / (8.223 × 10⁻¹⁹ J) = 2.41 × 10⁻⁷m = 241 nm
UV light wavelength is between 400 nm - 10 nm
Atoms are electrically neutral because they contain equal quantities of positively charged protons and negatively charged electrons. Electrons and protons have equal but opposite charges, so the result is no net charge. Ions are atoms that have gained or lost electrons.
