Answer:
1= Magnesium
2 = Option 3 = 1s² 2s² 2p⁶
Explanation:
An electrically neutral atom consist of equal number of protons and electrons.
The answer for 1st q is magnesium because the electronic configuration showed twelve number of electrons. The atomic number of magnesium is twelve that's why this configuration is of Mg.
Mg₁₂ = 1s² 2s² 2p⁶ 3s²
The second answer is option three because has atomic number ten and third electronic configuration have ten electrons.
Ne₁₀ = 1s² 2s² 2p⁶
It is stable electronic configuration. Neon is inert because of this electronic configuration. The outer most shell is completely filled.
The <span>formula for carbon tetrachloride is CCl4. The answer is letetr D. The rest of the choices do not answer the question above.</span>
Answer:
Elemental gold to have a Face-centered cubic structure.
Explanation:
From the information given:
Radius of gold = 144 pm
Its density = 19.32 g/cm³
Assuming the structure is a face-centered cubic structure, we can determine the density of the crystal by using the following:


a = 407 pm
In a unit cell, Volume (V) = a³
V = (407 pm)³
V = 6.74 × 10⁷ pm³
V = 6.74 × 10⁻²³ cm³
Recall that:
Net no. of an atom in an FCC unit cell = 4
Thus;


density d = 19.41 g/cm³
Similarly; For a body-centered cubic structure

where;
r = 144


a = 332.56 pm
In a unit cell, Volume V = a³
V = (332.56 pm)³
V = 3.68 × 10⁷ pm³
V 3.68 × 10⁻²³ cm³
Recall that:
Net no. of atoms in BCC cell = 2
∴


density =17.78 g/cm³
From the two calculate densities, we will realize that the density in the face-centered cubic structure is closer to the given density.
This makes the elemental gold to have a Face-centered cubic structure.
Answer:
B) They will react because X and Y can share two pairs of electrons to become stable
Explanation:
The electron configurations of two elements x and y are given :
X: 1s2 2s2 2p6
Y: 1s2 2s2 2p6 3s2 3p6
The statement that is true for both the elements is that, they both will react as they both can share two pairs of electrons to become stable.
To become stable the outermost shell or p orbital should have 8 electrons, so element X can gain 2 atoms to become stable.
Element Y can also react as it can also share two atoms to fulfill its 3p orbital and will stable.
Hence, the correct option is "B".