Answer: b. One atom transferring electrons to another atom
Explanation: An ionic bond is formed when an element completely transfers its valence electron to another element. The element which donates the electron is known as electropositive element and the element which accepts the electrons is known as electronegative element. This bond is formed between a metal and an non-metal.
Covalent bonds are formed by sharing of electrons between non metals
For example, In calcium iodide the one electron from calcium metal gets transferred to iodine atom and thus form an ionic bond to give 
Electronic configuration of calcium:
![[Ca]=1s^22s^22p^63s^23p^64s^2](https://tex.z-dn.net/?f=%5BCa%5D%3D1s%5E22s%5E22p%5E63s%5E23p%5E64s%5E2)
Calcium atom will lose two electron to gain noble gas configuration and form calcium cation with +2 charge.
![[Ca^{2+}]=1s^22s^22p^63s^23p^6](https://tex.z-dn.net/?f=%5BCa%5E%7B2%2B%7D%5D%3D1s%5E22s%5E22p%5E63s%5E23p%5E6)
Electronic configuration of iodine:
![[I]=1s^22s^22p^63s^23p^64s^23d^{10}4p^5](https://tex.z-dn.net/?f=%5BI%5D%3D1s%5E22s%5E22p%5E63s%5E23p%5E64s%5E23d%5E%7B10%7D4p%5E5)
Iodine atom will gain one electron to gain noble gas configuration and form iodide ion with -1 charge.
![[I^-]=1s^22s^22p^63s^23p^64s^23d^{10}4p^6](https://tex.z-dn.net/?f=%5BI%5E-%5D%3D1s%5E22s%5E22p%5E63s%5E23p%5E64s%5E23d%5E%7B10%7D4p%5E6)
Answer:
Na+ is positively charged as it loses an electron
Cl- is negatively charged as it gains an electron
Answer:
(a) Covalent bond. NF₃ (nitrogen trifluoride)
(b) Ionic bond. LiCl (lithium chloride)
Explanation:
<em>(a) N and F</em>
Nitrogen and fluorine are nonmetals, with high and similar electronegativities, so they form covalent bonds, in which they share pairs of electrons to complete the octet in their valence shell. N has 5 valence electrons so it will form 3 covalent bonds while each Cl has 7 valence electrons so it will form 1 covalent bond. As a result, the empirical formula is NF₃ (nitrogen trifluoride).
<em>(b) Li and Cl</em>
Lithium is a metal and Chlorine is a nonmetal. They have different electronegativities so they form an ionic bond, in which Cl gains 1 electron (7 valence e⁻) and Li loses 1 electron (1 valence e⁻). The empirical formula is LiCl (lithium chloride).
Step 1 - Discovering the ionic formula of Chromium (III) Carbonate
Chromium (III) Carbonate is formed by the ionic bonding between Chromium (III) (Cr(3+)) and Carbonate (CO3(2-)):

Step 2 - Finding the molar mass of the substance
To find the molar mass, we need to multiply the molar mass of each element by the number of times it appears in the formula of the substance and, finally, sum it all up.
The molar masses are 12 g/mol for C; 16 g/mol for O and 52 g/mol for Cr. We have thus:

The molar mass will be thus:

Step 3 - Finding the percent composition of carbon
As we saw in the previous step, the molar mass of Cr2(CO3)3 is 284 g/mol. From this molar mass, 36 g/mol come from C. We can set the following proportion:

The percent composition of Carbon is thus 12.7 %.
Answer:
Explanation:
Combustion reaction is given below,
C₂H₅OH(l) + 3O₂(g) ⇒ 2CO₂(g) + 3H₂O(g)
Provided that such a combustion has a normal enthalpy,
ΔH°rxn = -1270 kJ/mol
That would be 1 mol reacting to release of ethanol,
⇒ -1270 kJ of heat
Now,
0.383 Ethanol mol responds to release or unlock,
(c) Determine the final temperature of the air in the room after the combustion.
Given that :
specific heat c = 1.005 J/(g. °C)
m = 5.56 ×10⁴ g
Using the relation:
q = mcΔT
- 486.34 = 5.56 ×10⁴ × 1.005 × ΔT
ΔT= (486.34 × 1000 )/5.56×10⁴ × 1.005
ΔT= 836.88 °C
ΔT= T₂ - T₁
T₂ = ΔT + T₁
T₂ = 836.88 °C + 21.7°C
T₂ = 858.58 °C
Therefore, the final temperature of the air in the room after combustion is 858.58 °C