Temos os meios A e B. A luz no meio B com ângulo de incidência de 45º e n=V2, para o meio A com n=V3.

Which statement is true about effective nuclear charge?a. Effective nuclear charge decreases as we move to the right across a ro

MissTica

Answer:

Option b. Effective nuclear charge increases as we move to the right across a row in the periodic table

Explanation:

The effective nuclear charge is a measure of how strong the protons in the nucleus of an atom attract the outermost electrons of such atom.

The effective nuclear charge 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 effective nuclear charge, 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 effective nuclear charge 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.

3 0

3 years ago

A lacrosse ball that is thrown straight upwards reaches a maximum height of 4.5 m. At what initial velocity was it thrown? (note

shtirl [24]

Answer:

The initial velocity was 9.39 m/s

Explanation:

Lets explain how to solve the problem

The ball is thrown straight upward with initial velocity u

The ball reaches a maximum height of 4.5 m

At the maximum height velocity v = 0

The acceleration of gravity is -9.8 m/s²

We need to find the initial velocity

The best rule to find the initial velocity is v² = u² + 2ah, where v is

the final velocity, u is the initial velocity, a is the acceleration of

gravity and h is the height

⇒ v = 0 , h = 4.5 m , a = -9.8 m/s²

⇒ 0 = u² + 2(-9.8)(4.5)

⇒ 0 = u² - 88.2

Add 88.2 to both sides

⇒ 88.2 = u²

Take square root for both sides

⇒ u = 9.39 m/s

The initial velocity was 9.39 m/s

5 0

3 years ago

A cylinder 8 in in diameter and 3 ft long is concentric with a pipe of 8.25 in internal diameter. Between the cylinder and the p

Aleks [24]

Answer:

623.5lb

Explanation:

The answer is detailed in the attached photo

7 0

3 years ago

A current of 0.5 A flows in a 60 W light bulb when the voltage differences between the ends of the filament is 120 V. What is th

LuckyWell [14K]

Resistance = (voltage) / (current)

Resistance = (120 V) / (0.5 A)

Resistance = 240 ohms

Know what ? There might be too much information given in this question. I want to check, because it's possible that it might not even all fit together.

To calculate my answer, I only used the voltage and the current. I didn't use the "60 watts", and I'm curious to know whether it even fits with the given voltage and current.

Power = (voltage) times (current).

Power = (120 V) times (0.5 A)

Power = 60 watts

Well gadzooks and sure enough ! The three numbers given in the question all go together nicely.

And not only THAT !

The answer could have been calculated by using ANY TWO of them.

7 0

3 years ago

What is Force!????!?

spin [16.1K]

A force is a push or pull upon an object resulting from the object's interaction with another object.

4 0

3 years ago

Read 2 more answers