Question

2.1 - i can explain how ions are formed and determine the ionic charge for a given element.

1. what is the overall charge of an ionic compound?

a. positive b. negative c. neutral

1. when a sulfur becomes the sulfide ion, it has the same total amount of electrons as which element?
2. a. what is the total number of individual ions in the chemical formula mg₃(po₄)₂?

b. what is the total number of individual atoms in the compound in part a?

1. circle all the chemical species below that have a total of 36 electrons. circle all answers that fit this description.

a. cl⁻ b. kr c. se²⁻ d. sr e. sr²⁺ f. i

1. enter the missing information in the blank boxes.

ion name	protons	total electrons	charge (indicate sign)	number of e⁻ gained/lost (indicate gained or lost)	cation or anion
nitride
sulfide	-2
aluminum ion	13

the image to the right shows an atom of chlorine and sodium that are approaching to get very close to each other.

1. i. which of the following best describes what will happen?

a. na will gain 1 of cls valence electrons.
b. na will lose all of the 2 electrons in its innermost shell to cl.
c. cl will take nas 1 valence electron.
d. cl will give 1 of its valence electrons to na.
ii. which of the following describes the most accurate reasoning for the answer above?
a. the electrons in cl attract the electrons more strongly.
b. na is a larger atom than cl and will therefore
c. na has a larger positive pull to attract electrons toward itself more strongly.
d. cl has a much room available in its outermost shell to accept additional electrons compared to cl.

1. magnets are known to attract positively and negatively charged objects. however, when a magnet is brought close to a solid ionic compound, nothing happens. explain why a magnet does not stick to a solid ionic compound even though its composed of ions with + and - charges.
2. using the octet rule and lewis dot diagrams, illustrate electron transfer to show how the ions are formed when atoms of sodium (na) and sulfur (s) come together to form an ionic compound. once done, provide the chemical formula for the compound.

Explanation:

Step1: Determine overall charge of ionic compound

The overall charge of an ionic compound is neutral.

Step2: Analyze sulfide ion charge

A sulfur atom gains 2 electrons to become a sulfide ion ($S^{2 -}$), so its charge is negative.

Step3: Calculate number of ions and atoms in $Mg_3(PO_4)_2$

a. In $Mg_3(PO_4)_2$, there are 3 magnesium ions ($Mg^{2+}$) and 2 phosphate ions ($PO_4^{3 -}$), so the total number of individual ions is $3 + 2=5$.
b. For the number of individual atoms: 3 Mg atoms, 2 P atoms and $2\times4 = 8$ O atoms. So in total $3+2 + 8=13$ atoms.

Step4: Determine species with 36 electrons

a. $Cl^-$ has 17 + 1=18 electrons.
b. Kr has 36 electrons.
c. $Se^{2 -}$ has 34+ 2 = 36 electrons.
d. Sr has 38 electrons.
e. $Sr^{2+}$ has 38 - 2=36 electrons.
f. I has 53 electrons. So the species are b. Kr, c. $Se^{2 -}$, e. $Sr^{2+}$.

Step5: Fill in ion - related information

• Calcium ion: Protons = 20, Total electrons = 18, Charge = + 2, Number of $e^-$ lost = 2, Cation.
• Nitride: Protons = 7, Total electrons = 10, Charge=-3, Number of $e^-$ gained = 3, Anion.
• Sulfide: Protons = 16, Total electrons = 18, Charge=-2, Number of $e^-$ gained = 2, Anion.
• Aluminum ion: Protons = 13, Total electrons = 10, Charge = + 3, Number of $e^-$ lost = 3, Cation.

Step6: Analyze electron - transfer between Cl and Na

• Sodium (Na) will give 1 of its valence electrons to Chlorine (Cl).
• The most accurate reasoning is that Cl has a much stronger positive pull to attract electrons toward itself compared to Na because Cl has a higher electronegativity.

Step7: Explain magnet - ionic compound interaction

In a solid ionic compound, the ions are in a fixed lattice structure. Although the ions are charged, they are not free to move in the solid - state. So a magnet does not stick to a solid ionic compound as there are no free - moving charged particles to interact with the magnetic field.

Step8: Illustrate electron - transfer between Na and S

• Sodium has 1 valence electron and sulfur has 6 valence electrons.
• Each sodium atom will lose 1 electron and sulfur will gain 2 electrons.
• The Lewis dot diagram for Na: $Na\cdot$, for S: $\cdot\ddot{S}\cdot$.
• After electron - transfer, the chemical formula is $Na_2S$.

Answer:

1. neutral
2. negative
3. a. 5; b. 13
4. b. Kr, c. $Se^{2 -}$, e. $Sr^{2+}$
5. Calcium ion: Protons = 20, Total electrons = 18, Charge = + 2, Number of $e^-$ lost = 2, Cation; Nitride: Protons = 7, Total electrons = 10, Charge=-3, Number of $e^-$ gained = 3, Anion; Sulfide: Protons = 16, Total electrons = 18, Charge=-2, Number of $e^-$ gained = 2, Anion; Aluminum ion: Protons = 13, Total electrons = 10, Charge = + 3, Number of $e^-$ lost = 3, Cation
6. Sodium (Na) will give 1 of its valence electrons to Chlorine (Cl); Cl has a much stronger positive pull to attract electrons toward itself compared to Na
7. In a solid ionic compound, the ions are in a fixed lattice structure and are not free to move, so there are no free - moving charged particles to interact with the magnetic field.
8. The chemical formula is $Na_2S$