Answer: 3d
Explantion:
1) Period 4 contains the elements with atomic numbers 19 through 36.
2) The elements with atomic numbers 19 (K) and 20 (Ca) fill the orbital 4s.
3) After that, as Aufbau's rule may help you to remember, the energy of the orbitals 3d is lower than the energy of the orbtitals 4p. So, the element 21 (Sc) start fillind the orbital 3d.
There are ten 3d orbitals, so the elements 21 through 30 fill the 3d orbitals.
Those elements, called transition metals are: Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, and Zn.
When the 3d orbitals are full, the next elements in the same period 4, fill the six 4p orbitals.
The best and most correct answer among the choices provided by the question is the second choice , b. sodium hydroxide .
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Answer:7.229 grams of oxygen is formed by the complete reaction of 35.23 g of metallic sodium with oxygen at 130–200 °C, a process that generates sodium oxide, which in a separate stage absorbs oxygen: 4 Na + O2 → 2 Na2O. The ozone oxidizes the sodium to form sodium peroxide.
Answer:
The energy should be high.
Explanation:
Bonds do store energy and release it depending if it's endothermic or exothermic. The energy should be low because when a bond forms (endothermic) it releases heat, which helps form bonds. Having a high energy means the bond is absorbing energy, which helps break bonds (endothermic). How this helps!
The answer is balanced forces