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3 years ago

In the vertical columns of the periodic table:

Physics

1 answer:

vaieri [72.5K]3 years ago

4 0

Answer:

C. The number of shells increases from top to bottom

Explanation:

There are some trends about the periodic table, one of them is that in the vertical columns of periodic table, the number of shells increases from top to bottom.

From top to bottom in a periodic table, the number of electrons increases, thus more number of shells are needed to fill these electrons and the number of shells increases or we can say the atomic radius increases from top to bottom.

Hence, the correct option is "C".

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Which energy-level change shown in the diagram below emits electromagnetic radiation with the longest wavelength?

Andrej [43]

-- Electromagnetic radiation is emitted (spit out) when an electron
moves from a higher energy level to a lower one.

-- The greater the difference in energy between the two levels, the more
energy is emitted, and the shorter the wave;length of the emitted photon.

a) an electron moving from 4 to 5
This electron is moving to a HIGHER energy level. It doesn't emit anything.
In fact, you had to shoot energy INTO the atom to make the electron do this.

b) an electron moving from 5 to 2
This electron loses maybe something like 3.1 eV.

c) an electron moving from 6 to 1
This electron loses maybe something like 13.4 eV.

d) an electron moving from 2 to 1
This electron loses something like 10.2 eV.

The least energy is emitted by the electron in choice-b.
That one will emit the photon with the longest wavelength (shortest frequency).

This whole chart refers to the one electron in a hydrogen atom ...
how much energy it has at each level, how much energy is required
to boost it from one level to another, and how much energy it spits out
when it falls from one energy level to another.

The Balmer Series ... any drop that ends up at energy-level #2 ...
is the set of transitions that produce photons of visible light.

The Paschen Series are transitions that all emit less energy.
All of those emit infrared photons.

The Lyman series are transitions that all emit big energy.
All of those emit X-ray photons.

3 0

3 years ago

Explain 5 factors that act as a stimulant to change.

Tcecarenko [31]

Answer: Stimulant is a factor which brings change in the environment.

Explanation:

The external factors and internal factors both can develop changes in the environment of a living being. The external factors include sunlight, weather, touch, vibration, predation and others. The internal factors include the physiological and biochemical changes in the body, emotions and mental make up.

7 0

4 years ago

Read 2 more answers

A cup containing 200 g of hot water is taken off the stove placed on the kitchen table. Initially the water is at 75Degree C. bu

8090 [49]

Answer:

ΔH = -45.1872 kJ , where negative sign signifies heat loss.

Q = ΔH = -45.1872 kJ , where negative sign signifies heat loss.

S system = -0.141 kJ/K

S surroundings = 0.1536 kJ/K

S universe = -0.141 kJ/K + 0.1536 kJ/K = 0.0126 kJ/K

Explanation:

Given:

Cp = 4. 184 J/(mole. K)

T₁ = 75 ⁰C

T₂ = 21 ⁰C

Mass of water = 200 g = 0.2 kg

Since,

$\Delta H=m\times C\times (T_f-T_i)$

ΔH = 0.2*4.184*(21-75) kJ

ΔH = -45.1872 kJ , where negative sign signifies heat loss.

Since the process is at constant pressure

Q = ΔH = -45.1872 kJ , where negative sign signifies heat loss.

The conversion of T( °C) to T(K) is shown below:

T(K) = T( °C) + 273.15

T₁ = 75 ⁰C = 348 .15 K

T₂ = 21 ⁰C = 294.15 K

The entropy of the water is given by:

S = m×Cp×ln(T₂ /T₁)

S = 0.2*4.184*ln(294.15/348.15)

S system = -0.141 kJ/K

The heat gain by surroundings

dQ = -Qreaction = 45.1872 kJ

The entropy change of surroundings is

S surr = dQ/T₂ = 45.1872/294 .15

S surr = 0.1536 kJ/K

The entropy of universe is the sum total of the entropy of the system and the surroundings and thus,

S universe = Ssys + Ssurr

S universe = -0.141 kJ/K + 0.1536 kJ/K = 0.0126 kJ/K

4 0

3 years ago

During each cycle of operation a refrigerator absorbs 56 cal from the freezer compartment and expels 81 cal tothe room. If one c

Alexandra [31]

Answer:

138.18 minutes

Explanation:

$L_v$ = Latent heat of water at 0°C = 80 cal/g

m = Mass of water = 570 g

Heat removed for freezing

$Q=mL_v\\\Rightarrow Q=570\times 80\\\Rightarrow Q=45600\ cal$

Let N be the number of cycles and each cycle removes 56 cal from the freezer.

So,

$55\times N=45600\\\Rightarrow N=\frac{45600}{55}$

Each cycle takes 10 seconds so the total time would be

$\frac{45600}{55}\times \frac{10}{60}=138.18\ minutes$

The total time taken to freeze 138.18 minutes

6 0

3 years ago

If the current flowing through an electric heater increases from 6 to 12 amp while the voltage remains the same, the heat produc

Ainat [17]

Q=l^2 times R times t
Where Q - heat, I -current, R - resistance and t is time

If you increase I twice (and it's squared), than Q gonna went up 4 times (2 squared).

Choose last

8 0

4 years ago

Read 2 more answers