Answer:
Option b. Effective nuclear charge increases as we move to the right across a row in the periodic table
Explanation:
The <em>effective nuclear charge </em>is a measure of how strong the protons in the nucleus of an atom attract the outermost electrons of such atom.
The <em>effective nuclear charge</em> is the net positive charge experienced by valence electrons and is calculated (as an approximation) by the equation: Zeff = Z – S, where Z is the atomic number and S is the number of shielding electrons.
The shielding electrons are those electrons in between the interesting electrons and the nucleus of the atom.
Since the shielding electrons are closer to the nucleus, they repel the outermost electrons and so cancel some of the attraction exerted by the positive charge of the nucleus, meaning that the outermost electrons feel less the efect of attraction of the protons. That is why in the equation of Zeff, the shielding electrons (S) subtract the total from the atomic number Z.
The <em>effective nuclear charge</em>, then, is responsible for some properties and trends in the periodic table. Here, you can see how this explains the trend of the atomic radius (size of the atom) accross a row in the periodic table.
- As the<em> effective nuclear charge</em> is larger, in a same row of the periodic table, the shielding effect is lower, the outermost electrons are more strongly attracted by the nucleus, and the size of the atoms decrease. That is why as we move to the right in the periodic table, the size of the atoms decrease.
Answer:
Fr = 48 [N] forward.
Explanation:
Suppose the movement is on the X axis, in this way we have the force of the engine that produces the movement to the right, while the force produced by the brake causes the vehicle to decrease its speed in this way the sign must be negative.
∑F = Fr
![F_{engine}-F_{brake} =F_{r}\\F_{r}=79-31\\F_{r}=48[N]](https://tex.z-dn.net/?f=F_%7Bengine%7D-F_%7Bbrake%7D%20%3DF_%7Br%7D%5C%5CF_%7Br%7D%3D79-31%5C%5CF_%7Br%7D%3D48%5BN%5D)
The movement remains forward, since the force produced by the movement is greater than the braking force.
Answer:
the index of refraction of the second medium is lower
Explanation:
take an exaple of a light ray from air to water that is optically denser the ray is refracted to the normal thus lowering its index of refraction
Answer:
change in entropy is 3.3034 × 
Explanation:
give data
thermal energy Q = 155 J
temperature T = 340 K
to find out
change in entropy
solution
we know change in entropy formula that is
change in entropy = Q / ( K×T ) ..............1
here K is boltzmann constant that is 1.38 × 
kg-m²/s²
put these value in equation 1 we get
change in entropy = Q / ( K × T )
change in entropy = 155 / ( 1.38 × × 340 )
change in entropy = 3.3034 ×
so change in entropy is 3.3034 ×
Density = Mass/Volume
=> 5g/cm³ = 45kg/Volume
=> 0.005kg/cm³ = 45kg/Volume
=> Volume = (cm³×45kg)/0.005kg
=> Volume = 9000kg/cm³
