All categories

2 years ago

How does one determine the number of core electrons an atom has?

Chemistry

2 answers:

scoundrel [369]2 years ago

4 0

Answer: Subtract the number of valence electrons(outer most shell electrons) from the atomic number of an atom.

Explanation: The total number of electrons for an atom equals to its atomic number. Electrons are present in different shells. Electrons present in outer most shell(valence shell) are known as valence electrons and rest of the electrons present in inner shells are known as core electrons.

So, to determine the number of electrons we subtract the valence electrons from atomic number.

For example, atomic number of N (nitrogen) is 7. It has 5 valence electrons.

Number of core electrons for N = 7 - 5 = 2

Aleonysh [2.5K]2 years ago

3 0

Subtract the group number from the atomic number.

Read more about Chemical Reaction

brainly.com/question/11231920

#SPJ1

7 0

1 year ago

using the equation you wrote determine how many moles of butane c4h10 are needed to react with 5.5 moles of oxygen

GaryK [48]

Answer:

0.846 moles.

Explanation:

This is a stichiometric problem.

The balanced equation of complete combustion of butane is:

C₄H₁₀ + 6.5 O₂ → 4 CO₂ + 5 H₂O

It is clear from the stichiometry of the balanced equation that complete combustion of 1.0 mole of butane needs 6.5 moles of O₂ to produce 4 moles of CO₂ and 5 moles of H₂O.

Using cross multiplication:

1.0 mole of C₄H₁₀ reacts with → 6.5 moles of O₂

??? moles of C₄H₁₀ are needed to react with → 5.5 moles of O₂

The number of moles of C₄H₁₀ that are needed to react with 5.5 moles of O₂ = (1.0 x 5.5 moles of O₂) / (6.5 moles of O₂) = 0.846 moles.

3 0

2 years ago

What is the ground-state electron configuration of a neutral atom of manganese?.

Alchen [17]

Explanation:

elctronic configuration of manganese

Mn=1s²2s²2p⁶3s²3p⁶4s²3d⁵

ground state

Mn=Ar3d⁵4s²

note that Ar is argon

3 0

2 years ago

Determine if these molecules and ion are polar.

Colt1911 [192]

Answer:

a. Polar

b. Polar

c. Non-polar

d. Non-polar

Explanation:

a. $H_3O^+$ , hydronium cation contains a positive charge. Just as any other ion, it is polar, as it has a net charge.

b. $H_2S$ has the same shape as water. There are two lone pairs on sulfur atom which produce an overall dipole moment in this molecule, the bent structure is polar.

c. $PCl_5$ is non-polar, as the central atom, phosphorus, doesn't contain any lone pairs, all the dipole moments cancel out: two dipole moments in the vertical plane, P-Cl, and three P-Cl dipoles in the horizontal plane within a trigonal bipyramidal shape.

d. $CF_4$ is non-polar, since it's a tetrahedral molecule with no lone pairs on carbon atom, all four C-F dipole moments cancel out to yield a net 0 dipole moment.

3 0

2 years ago

An energy of 6.8 x 10^-19 J/atom is required to cause an aluminum atom on a metal surface to lose an electron.

Nana76 [90]

Wavelength of the light is 2.9 × 10⁻⁷ m.

Explanation:

Planck - Einstein equation shows the relationship between the energy of a photon and its frequency, and they are directly proportional to each other and it is given by the equation as E = hν,

where E is the energy of the photon

h is the Planck's constant = 6.626 × 10⁻³⁴ J s

ν is the frequency

From the above equation, we can find the frequency by rearranging the equation as,

ν = $$ \frac{E}{h}$ = $$ \frac{6.8 \times 10^{-19}}{6.626\times10^{-34}} = 1.03\times10^{15} s^{-1}$

Now the frequency and the wavelength are in inverse relationship with each other.

ν × λ = c

It can be rearranged to get λ as,

λ = c / ν

= $$\frac{3\times 10^{8} ms^{-1}}{1.03\times10^{15}s^{-1}} = 2.9\times 10^{-7} m$

So wavelength is 2.9 × 10⁻⁷ m.

6 0

3 years ago