1) the elements most likely to form more than one type of ion are the

a) transition metals.
b) alkali metals.
c) halogens.
d) alkaline earth metals.

2) the name iron(11) indicates that a compound contains

a) iron ions with an 11+ charge.
b) iron ions with a 2+ charge.
c) iron ions with a negative charge.
d) two types of iron ions.

These are two questions and two answers.


Question 1) The elements most likely to form more than one type of ion are the .


option A) transition metals.

Jusitification:

1) The elements form ions by gaining or losing electrons. By gaining electrons, theY form anions (negative iones); by losing electrons, they form cations (positive ions).


2) The valence shell of the akaly metals is the type ns¹, which means that they have one electron in the valence shell. Then, they only can form one kind of ion which has the configuration of the previous noble gas (n-1)s²(n-1)p⁶ with 1+ charge.


3) The halogens have valence shell of the type ns²np⁵. That means that easily gain 1 electron to complete the valence shell ns²np₆ (the configuration of the next noble gas), with charge 1-. Gaining 5 electrons or losing more electrons than 1 is very disfavourable, so that is the only kind of ion they form.


4) The valence shells of alkaline earth metals are of the kind ns². So, the most favourable energetic ion is formed by losing 2 electrons and so taking the configuration of the previous noble gas, with charge 2+. That is the only type of ion they form.


5) Transition metals have electrons in the orbitals d, which are very similar in energy, and so they might loose 1, 2, or 3, electrons fo form ions with charges 1+, 2+, or 3+ respectively.


Question 2) The name iron(II) indicates that a compound contains .

A) iron ions with an II+ charge.

B) iron ions with a 2+ charge.

C) iron ions with a negative charge.
D) two types of iron ions.


option B) iron ions with a 2+ charge.


The oxidation state may be indicated as Roman numerals, in this case II, or as a conventional number with its charge.


Iron, a transition metal, may loose 2 or 3 valence electrons. When it loses 2 electrons it forms an ion (cation) with positive charge 2. So, it is iron 2+