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3 years ago

Which element is more metallic among beriliyum or calcium? Give reason

1 answer:

3 0

Both elements are in the same group but valence electrons of calcium are further away from the nucleus. They are not strongly held by the nucleus, hence are readily released. And readily released electrons means higher reactivity. Easy on the alkaline earth metals.

I hope this helps!

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Carbon-12 contains 6 protons and 6 neutrons. The radius of the nucleus is approximately 2.7 fm (femtometers) and the radius of t

Slav-nsk [51]

Explanation:

Let us assume that volumes is equal to spheres volume of nucleus.

fm = femto meter = $10^{-15}$

pm = pico meter = $10^{-12}$

Hence, calculate the volume as follows.

V = $\frac{4}{3} \times \pi \times r^{3}$

= $\frac{4}{3} \times 3.14 \times (2.7)^{3}$

= 82.4481 $fm^{3}$ (cubic femtometers)

or, = 82 $fm^{3}$

Now, we will calculate the volume of the atom as follows.

V = $\frac{4}{3} \times \pi \times r^{3}$

= $\frac{4}{3} \times 3.14 \times (70)^{3}$

= 1436758.4 $pm^{3}$ (cubic picometers)

thus, we can conclude that volume of the nucleus is 82 $fm^{3}$ and volume of the atom is 1436758.4 $pm^{3}$ .

7 0

3 years ago

Ultraviolet radiation and radiation of shorter wavelengths can damage biological molecules because they carry enough energy to b

Alja [10]

Answer:

439.7nm

Explanation:

Energy of a quantum can be calculated using below formula

E=hv...........eqn(1)

But v=λ/ c .........eqn(2)

If we substitute eqn(2) into eqn(1) we have

E= hc/(λ)

Where E= energy

h= Plank's constant= 6.62607004 × 10-34 m2 kg / s

c= speed of light

c= 2.998 × 10^8 m/s

λ= wavelength= ?

But the energy was given in Kj , it must be converted to Kj/ photon for unit consistency.

Energy E= 272 kJ/mol × 1mol/6.02× 10^23

Energy= 451.83× 10^-24 Kj/ photon

E= hc/(λ)...........eqn(1)

If we make λ subject of the formula

λ= hc/E

Then substitute the values we have

λ= [(6.626 × 10^-34) × (2.998 × 10^8)]/451.83× 10^-24

λ=(0.00043965) × (1Kj/1000J) × (10^9nm/1m)

λ=439.7nm

Hence, the longest wavelength of radiation with enough energy to break carbon-sulfur bonds is 439.7nm

4 0

2 years ago

Which term names the group of organisms able to interbreed and produce fertile offspring?

vladimir2022 [97]

Answer:

Species

Explanation:

Species is the group of organisms able to interbreed and produce fertile offspring.

Let's break down each word in the question:

"Organisms" means living thing. It can be a plant or animal like we usually think of, but it also includes the really small single-celled living things like some bacteria.

"Interbreed" means to mate with each other.

"Fertile" means that the living thing can also have babies.

"Offspring" means the children that are born.

"Fertile offspring" means that the children that are made must be able to have babies of their own. For example, if a frog and a bird could interbreed, they might produce offspring (children). But, if those frog-birds cannot also have children, then frog-bird is not a species.

7 0

3 years ago

Help me find the word elliptical

maria [59]

Omg where is it?? i’ve been looking for a long time

7 0

2 years ago

Complete the following single replacement reaction. If they don’t react, just write “NR”

Kipish [7]

Here we have to complete the given single replacement reactions.

The replacement reactions are-

1) Fe (s) + CuCl₂ (aq) → FeCl₂ (aq) + Cu (s)

2) Cu (s) + FeCl₂ (aq) → NA

3) K (s) + NiBr₂ (aq) → NA

4) Ni (s) + KBr (aq) → NiBr₂ (aq) + K (s)

5) Zn (s) + Ca(NO₃)₂ (aq) → Zn(NO₃)₂ (aq) + Ca (s)

6) Ca (s) + Zn(NO₃)₂ (aq) → NA

The replacement reactions can be explained in light of the redox potential.

The standard reduction potential of the half cells involved in these reactions are:

Fe²⁺ + 2e → Fe (E° = -0.441V); Cu²⁺ + 2e → Cu (E° = 0.674V)

Ni²⁺ + 2e → Ni (E° = -0.23V); Zn²⁺ + 2e → Zn (E° = -0.763V)

We know the half cell reactions in which the standard reduction potentials are positive are allowed.

1) The reaction is possible as Cu²⁺/Cu and Fe/Fe²⁺ standard reduction potentials are positive.

2) The reaction is not possible as Cu/Cu²⁺ and Fe²⁺/Fe standard reduction potentials are negative.

3) The reaction is not possible as Ni²⁺/Ni standard reduction potential is negative.

4) The reaction is possible as Ni/Ni²⁺ standard reduction potential is positive.

5) The reaction is possible as Zn/Zn²⁺ standard reduction potential is positive.

6) The reaction is possible as Zn²⁺/Zn standard reduction potential is negative.

4 0

2 years ago