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Zarrin [17]
2 years ago
15

Which of the following sequences of elements would all have four valence electrons?

Chemistry
1 answer:
timama [110]2 years ago
8 0

Answer:b

Explanation:

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What is the value of c?<br> 56.70
Gennadij [26K]

Due to the lack of information provided, the best I can give you is this:

In Chemistry, the letter c most commonly refers to specific heat, which is present in the ratio J/g°C.

Hope it helps :)

6 0
3 years ago
Boron occurs naturally as two isotopes. What is the difference between these isotopes?
Murrr4er [49]

Answer:

Number of neutrons and stability

Explanation:

An isotope of an element is basically the same element but with different number of neutrons. For example here, boron can exist in the forms of boron-10 and boron-11, and so the latter would have one more neutron than the former one.

Adding an extra neutron may or may not disrupt the strong force that much, and so the half-life and stability of the new isotope can be slightly different than its most stable one.

8 0
2 years ago
20cm³ of methane gas was burnt in 20cm³ of oxygen. write a balanced chemical equation for the reaction and determine which of th
solniwko [45]

Answer:

CH4 +O2 => CO2 + 2 H2O

None were in excess

Explanation:

Equation for the reaction is,

CH4 + O2 =>CO2 +2 H2O

No of moles of CH4 = (20 /1000)/24 =0.02 /24 = 0.00083

No of moles of O2 =20 /24000 = 0.0083

CH4 : O2 = 1:1

THEREFORE

None of the gases were in excess.

7 0
3 years ago
Helium is the lightest noble gas and the second most abundant element (after hydrogen) in the universe. The mass of a helium−4 a
dmitriy555 [2]

<u>Answer:</u> The fraction of atom's mass contributed by nucleus is 0.99

<u>Explanation:</u>

Nucleons are defined as the sub-atomic particles which are present in the nucleus of an atom. Nucleons are protons and neutrons.

The isotopic symbol of Helium-4 atom is _2^4\textrm{He}

Number of electrons = 2

Number of protons = 2

Number of neutrons = 4 - 2 = 2

We are given:

Mass of He-4 atom = 6.64648\times 10^{-24}g

Mass of 1 electron = 9.10939\times 10^{-28}g

Calculating the mass contributed by the nucleus = m_{He}-2(m_e)

Mass of the nucleus of He-4 atom = 6.64648\times 10^{-24}-(2\times (9.10939\times 10^{-28}))=(6.64648-0.0018219)\times 10^{-24}=6.64466\times 10^{-24}

To calculate the fraction of atom's mass contributed by the nucleus, we use the equation:

\text{Fraction of atom's mass contributed by nucleus}=\frac{\text{Mass of nucleus}}{\text{Mass of atom}}

Putting values in above equation, we get:

\text{Fraction of atom's mass contributed by nucleus}=\frac{6.64466\times 10^{-24}g}{6.64648\times 10^{-24}g}=0.99

Hence, the fraction of atom's mass contributed by nucleus is 0.99

8 0
3 years ago
Which of the following types of radiation has the greatest ability to penetrate matter
Tcecarenko [31]
You did not specify the types, but I believe the answer would be gamma radiation.
7 0
3 years ago
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