To start, consult the periodic table to pinpoint the element with an average atomic mass of 24.3. The amu is simply the number listed under the element, leading us to conclude that Mg is the answer.
Fe 3+ + SCN- --> FeSCN 2+
<span>.......Fe 3+.......SCN-.........FeSCN 2+ </span>
<span>I.......0.04..........0.001.............. </span>
<span>C........-x...............-x............. </span>
<span>E.....0.04-x.....0.001-x...........x </span>
<span>Keq = 203.4 = x / (0.04-x)(0.001-x) </span>
<span>203.4 = x / (x^2 - 0.041x + 4x10^-5) </span>
<span>203.4x^2 - 8.34x + 0.00094 = x </span>
<span>203.4x^2 - 9.34x + 0.00094 = 0 </span>
<span>x = -0.0001M or 0.0458M </span>
<span>therefore, according to the calculated Keq, all of the SCN- and Fe 3+ would be fully converted into FeSCN 2+</span>
Response:
Ionic, metal, organic
Clarification:
For this scenario, we should examine each compound:
-) 
In this compound, there is a non-metal atom (Cl) paired with a metal atom (Ca). This leads to a significant difference in electronegativity, indicating that an ionic bond will form. Ions can be generated:

The positive ion would be
while the negative ion is
. Thus, we have an ionic compound.
-) 
Here, we are looking at a single atom. Consulting the periodic table shows that this atom belongs to the transition metals section (central part of the periodic table). Hence, Cu (Copper) is identified as a metal.
-) 
Within this molecule, carbon and hydrogen are linked by single bonds. The difference in electronegativity between C and H is insufficient to lead to ion formation. Therefore, we have covalent bonds. This property is typical of organic compounds. (Refer to figure 1)
Answer:
The correct choice is: option A.
Justification:
To address this inquiry, we need to evaluate the total number of electrons each orbital can accommodate.
Orbital Number of electrons
s 2
p 6
d 10
f 14
Provided options:
A. 1s² 2s² 2p⁶ 3s² This configuration is valid as it aligns with the permitted number of electrons in each orbital and follows the correct sequence.
B. 1s² 2s² 2p⁶ 3s² 3d⁴ This configuration is not accurate because
3d⁴ should follow 3p.
C. 1s² 2s² 2d¹⁰ 2p³ This is incorrect since 2d¹⁰ is not a valid orbital.
D. 1s² 2s^s 2p³ 2d¹⁰ This option contains two errors; s as an exponent does not exist, and 2d¹⁰ is also an invalid description.
According to the periodic table:
the molar mass of barium is 137.2 grams
the molar mass of oxygen is 16 grams
the molar mass of hydrogen is 1 gram
The molar mass of Ba(OH)2 can be calculated as 137.2 + 2(16) + 2(1) = 171.2 grams.
The molar mass of 4H2O is computed as 4 [2(1) + 16] = 72 grams.
Consequently, the molar mass of Ba(OH)2·4H2O is 171.2 + 72 = 243.2 grams.
Therefore, a sample weighing 243.2 grams of <span>barium hydroxide tetrahydrate includes 72 grams of water, meaning that within 92.8 grams, the mass of water would be:
mass of water in 92.8 grams = (92.8 x 72) / 243.2 = 27.474 grams.
Thus, when heating a 92.8 gram sample of Ba(OH)2·4H2O (barium hydroxide tetrahydrate), 27.474 grams of water will be emitted.</span>