Which of the following happens when unbalanced forces act on an object? The object remains stationary. The object moves with the
2 answers:
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The correct statements are "Each orbit holds a fixed number of electrons" and "The n=1 orbit can only hold two electrons." According to the Bohr model, the maximum number of electrons that can occupy an orbit is given by , where n is the number of the orbit. For instance, when n=1 it means
. This particular orbit can only hold up to two electrons. Even though the electrons can gain energy and move to higher orbits or electrons from higher orbits can lose energy and drop to the n=1 level, the energy level would not allow more electrons to enter the orbit once it is full. Again the octet rule, which states that atoms achieve stability by having 8 valence electrons, limits the maximum number of electrons that can be occupied by an orbit. The gain and loss of electrons is done to achieve the noble gas configuration and once that is reached no more electron can be added to an orbit
Answer:
A) & B)
Explanation:
First, the numbers 12 and 13 represent the <em>atomic mass number</em> of the atoms.
- So, A) is true: thus Carbon12 and Carbon 13 have different mass numbers.
The <em>mass number</em> is equal to the total number of protons and neutrons. Consider that any element has the same number of protons, regardless of the number of neutrons. The number of protons in Carbon is 6.
The amount of neutrons can be calculated by: <em>mass number </em>minus <em>number of protons.</em>
For Carbon 12:
For Carbon 13:
- B) is true, we just proved they have different amounts of neutrons.
In order for the charge of the atom to be neutral, the amount of electrons must be equal to the number of protons (as they have opposite charges). And we now know that the number of protons in Carbon12 and Carbon13 are always the same
- C) is false, the number of electrons is the same in both atoms
The atomic charges in both are neutral, due to the fact that they have the same amount of protons and electrons in both cases. Is only the neutrons (thus the mass numbers)that change
- D) is false, they have equal atomic charges
Answer:
minimum number of photon is 4.05 ×
Explanation:
given data
energy = 50 keV = 50 × eV = 50 ×
× 1.602×
J
thickness = 10^-3
contrast = 1%
to find out
number of incident photons
solution
we know here equation that is
E = n × h × ν .......................1
put here all these value
50 × = n × 6.6×
× c/ 1×
50 × × 1.602×
= n × 6.6×
×( 3 ×
/ 1×
)
solve it and find n
n = 4.05 ×
so here minimum number of photon is 4.05 ×