# Which set of elements is in the correct order of increasing first ionization energy? a. li, na, k b.

Which set of elements is in the correct order of increasing first ionization energy?

a. li, na, k
b. f, o, n
c. ca, mg, be
d. si, p, s

## This Post Has 10 Comments

1. khamyah says:

1)5

2) Al3+ and Se2-

3)S2−, Cl−, K+    and  Na+, Mg2+, Al3+

Explanation:

1) Atomic number of Fe is 26. This means it has 26 protons and 26 electrons.

The electron configuration is as followed:

⇒Fe-1s2 2s2 2p6 3s2 3p6 3d6 4s2

⇒a neutral atom of iron would have two electrons in the 4s sublevel and six electrons in the 3d sublevel.

Fe3+ has 3 electrons less than Fe, so 23 electrons.

⇒The electron configuration for the Fe3+ ion is 1s2 2s2 2p6 3s2 3p6 3d5.  ⇒The positive charge of three in this ion shows that the atom lost three electrons.

⇒Electrons are taken from the outermost electron shell first, eliminating the two in the 4s sublevel. The other lost electron is then taken from the 3d sublevel.

⇒d subshell can occupy 10 electrons (in 5 orbitals). Pairing of electrons take place only after each orbital is singly occupied (Hund’s rule).

⇒ So, there are 5 electrons in the d subshell. So, each d orbital is singly occupied (unpaired).

⇒ This means there are 5 unpaired electrons in Fe3+

2) noble gas configuration means they have 8 electrons on the the outer shell.

⇒Cr3+ : Cr has 24 electrons of which 1 electron on the outer shell, so Cr3+ is not in the noble gass electron configuration

⇒1 s 2  2 s 2  2 p 6  3 s 2  3 p 6  4 s 0  3 d 3

⇒Note that it is  4 s 1  3 d 5  and not  4 s 2  3 d 4  because a half filled  d  orbital is more stable than a partially filled  d  orbital.

⇒Al3+: Al has 13 electrons, of which 3 are on the outer shell. Al3+ has 3electrons less, this means it loses the 3 electrons on the outer shell. So Al3+ has 10 electrons, of which 8 on the outer shell. This means it's in the noble gas electron configuration.

⇒The electron configuration of an aluminum ion, Al3+, is 1s2, 2s2, 2p6

⇒Se2-: Se has 34 electrons, of which 6 are on the outer shell. Se2- has 2 electrons more, this means it gains 2 electrons on the outer shell. So Se2- has 36 electrons, of which 8 on the outer shell. This means it's in the noble gas electron configuration.

⇒1 s 2  2 s 2 2 p 6  3 s 2  3 p 6  3 d 10  4 s 2  4 p 6

3) Isoelectronic species means those species which have same no. of total electrons :

S2-, Cl-,K+ :

⇒S has 16 electrons, S2- has 2 electrons more so 18 electrons

⇒Cl has 17 electrons,Cl- has 1 electron more so 18 electrons

⇒K has 19 electrons, K+ has 1 electron less so 18 electrons

⇔This is an isoelectronic set because they all have 18 electrons

⇔in order of increasing radius : S2- > Cl- > Al3+ : because in Sé- are the most electrons added.

Na+,Mg2+,Al3+

⇒Na has 11 electrons, Na+ has 1 electron less so 10 electrons

⇒Mg has 12 electrons, Mg2+ has 2 electrons less so 10 electrons

⇒Al has 13 electrons, Al3+ has 3 electrons less so 10 electrons

⇔This is an isoelectronic set because they all have 10 electrons

⇔in order of increasing radius : Na+ >Mg2+ > Al3+ : because in Sé- are the most electrons added.

Na+,K+,Li+

⇒Na has 11 electrons, Na+ has 1 electron less so 10 electrons

⇒K has 19 electrons, K+ has 1 electron less so 18 electrons

⇒Li has 3 electrons, Li+ has 1 electron less so 2 electrons

⇔This is no isoelectronic set

4) ⇒Pb is a metal. It's part of the p-block and the carbon group. It forms a Pb-ion ( Pb2+)

⇒ K is an alkalimetal ( so part of the metals). It forms K-ion (K+)

⇒ Xe is a nonmetal and part of the noble gasses. It doesn't form an ion, because it has 8 electrons on the outer shell, why it's stable.

⇒Al is a metal. It forms an Al3+ ion

⇒Iodine is a halogene., so a nonmetal. It forms I-, ion

2. Okeh4001 says:

1) noble gases2) by increasing atomic number3) noble gases

3. alexwlodko says:

i don't understand this chemistry but you can look at me im cute

Explanation:

$Which of the sets of elements are not in order of increasing force of attraction on the outermost el$

4. u8p4 says:

smart people

Explanation:

5. rebecca7415 says:

The increasing order of conductivity is O< Ge< Mn.

Explanation:

Electrical conductivity is defined as the measure of the ability of a material to conduct electrical current through it. The conductivity depends on the atomic and molecular structure of the material.

Metals are good conductors because they have a structure with many electrons with weak bonds, and this allows their movement instead non-metals have between four and eight valence electrons, which lack this tendency.

The conductivity increases in the periodic table from top to bottom and from right to left.

oxygen is a nonmetal therefore it is a bad conductor.

Germanium is a metalloid whose conductivity is greater than a nonmetal and worst than a metal.

Manganese is a metal,in this case, it is a good conductor.

6. elondamason says:

D hope this help 🙂

7. anggar20 says:

dude im sorry give me a second to read it again In Ionic bonds the electrons are between the balance shells

Ionic bonds are formed between and

In covalent bonds pairs of electrons are between non-metal atoms

In the following Ionic bond which element is the metal and non metal

Na:

Cl:

Water is a molecule

Non-polar bonds are composed of atoms

Polar bonds are composed of atoms

Non-polar molecules are

Polar molecules are

Explanation:

8. akatsionis25 says:

The mean of three numbers x1,x2,x3 can be obtained by a calculus. The first step of the algorithm is

1) $mean(x1,x2,x3) = \frac{x1+x2+x3}{3}$

In order to obtain the median, maximun and minumun of x1, x2 and x3, we can compare x1 and x2. The smaller of those numbers will be compared to x3 and, if x3 is even smaller, then x3 is the minimun, the other small number is the median, and the remaining number is the maximun. Otherwise, we compare x3 with the bigger number to find median and maximun. To summarize:

2) compare x1 with x2. The bigger of the two numbers will be called 's' (for  small) and the smaller will be called 'b' (from big).

3) compare x3 with s. The smaller of this subset will be the minimun of the entire set of 3 elements.

4) Check if x3 is the minimun, in that case, s is the median, because s is between x3 and b. We also conclude that b is the maximun

5) if x3 in not the minimun, then compare it with b. The bigger element between the two of them will be the maximun of the set, and the smaller one will be the median.

I hope it helps you!

9. Ericapab says:

the first answer is correct and 8 is O, Ge, Mn

Explanation:

10. glocurlsprinces says:

The correct option is: C. Ca, Mg, Be

Explanation:

First ionization energy of a chemical element refers to the energy needed to completely remove one valence electron from the outermost electron shell or valence shell of a gaseous atom.

The ionization energy decreases down the group and increases across a period. Elements having stable half-filled or fully-filled electron configuration have high ionization energy. Also, elements having high electronegativity have higher ionization energy.

Thus the ionization energy of the second group elements i.e. alkaline earth metals, decreases as we go down the group from beryllium to calcium.

Therefore, the increasing order of first ionization energy is correct in this set: C. Ca, Mg, Be.