<u>Answer:</u> The correct answer is d-block.
<u>Explanation:</u>
Chromium is the 24th element of the periodic table. It belongs to period 4 and Group 6 of the periodic table.
The number of electrons present in this element are 24 because number of electrons is equal to the atomic number of the element.
Electronic configuration of this element is: ![[Ar]4s^23d^4](https://tex.z-dn.net/?f=%5BAr%5D4s%5E23d%5E4)
As, the last electron is entering the d-orbital. Hence, this element belongs to d-block of the periodic table.
This is the answer for the question above:
In order to solve this, first use stoichiometry for the energy in kJ released by, converting grams of CuO2 to moles:
<span>56.96g*(1 mole/143.09 g)=0.41904 moles of Cu2O </span>
<span>2 moles of Cu2O=-292.0kJ Convert 0.41904 moles of Cu2O to kJ. </span>
<span>Finally, solve for kJ: </span>
<span>0.41904 moles of Cu2O*(-292.0kJ/2 moles of Cu2O)=-61.18 kJ of energy released</span>
<span>Dark matter has been given this name because it doesn’t seem to interact with regular matter in any way. It doesn’t collide with it, or absorb energy from it. We can’t see it or detect it with any of our instruments. We only know it’s there because we can see the effect of its gravity.</span>