Answer:
the answer is D
Explanation:
percentage composition= mole of the substance divided by the total molar mass of the compound multiplied by 100.
Answer:
E = 19.89×10⁻¹⁶ J
λ = 1×10⁻¹ nm
Explanation:
Given data:
Frequency of xray = 3×10¹⁸ Hz
Wavelength of xray = ?
Energy of xray = ?
Solution:
speed of wave = wavelength × frequency
speed = 3×10⁸ m/s
3×10⁸ m/s = λ ×3×10¹⁸ s⁻¹
λ = 3×10⁸ m/s / 3×10¹⁸ s⁻¹
λ = 1×10⁻¹⁰m
m to nm:
λ = 1×10⁻¹⁰m×10⁹
λ = 1×10⁻¹ nm
Energy of x-ray:
E = h.f
h = plancks constant = 6.63×10⁻³⁴ Js
by putting values,
E = 6.63×10⁻³⁴ Js ×3×10¹⁸ s⁻
¹
E = 19.89×10⁻¹⁶ J
Since nickles atomicnumber is 28, that means it has 28 protons, which are positively charged. To cancel out the positive charge and make it nuetral, there isalso 28 electrons which are negatively charged.
Nickel has 31 neutrons because an atoms mass is the number of protons + neutrons. The # of protons is 28. The mass # is 59. So, there are 31 neutrons.
Answer:
an isotope has the same number of protons but a different number of neutrons than the other atoms of the same element.
