Question

Consider the reaction between sodium metal and fluorine ( \(\mathbf{F}_{2}\) ) gas to form sodium fluoride. Using oxidation states, how many electrons would each sodium atom lose, and how many electrons would each fluorine atom gain? How many sodium atoms are needed to react with one fluorine molecule? Write a balanced equation for this reaction.

Short answer

Each sodium atom loses 1 electron, while each fluorine atom gains 1 electron. Two sodium atoms are needed to react with one fluorine molecule. The balanced equation for this reaction is: \( 2 Na + F_{2} \rightarrow 2 NaF \)

Step-by-step solution

Determine the oxidation states of sodium and fluorine atoms

Observe the periodic table to find the oxidation states of Sodium (Na) and Fluorine (F). Sodium is in Group 1 and has an oxidation state of +1. Fluorine is in Group 17 and has an oxidation state of -1.

Identify the number of electrons lost or gained

Since Sodium has an oxidation state of +1, it means that each sodium atom will lose 1 electron. Fluorine has an oxidation state of -1, meaning that each fluorine atom will gain 1 electron.

Determine the ratio of sodium to fluorine atoms needed for a balanced reaction

We have one molecule of Fluorine gas (\(F_2\)), which contains two fluorine atoms. Each fluorine atom gains 1 electron. So, it needs a total of 2 electrons to be completely reduced. Since a sodium atom loses 1 electron during oxidation, we will need 2 sodium atoms to provide 2 electrons to the fluorine atoms.

Write a balanced equation for the reaction

Our balanced equation will include 2 sodium atoms reacting with 1 fluorine molecule to produce 2 sodium fluoride molecules. The balanced equation is: \[ 2 Na + F_{2} \rightarrow 2 NaF \]

Key concepts

Redox Reactions

Redox reactions are fundamental processes in chemistry where the oxidation states of atoms change due to the transfer of electrons. These reactions are essential in numerous chemical and biological systems, from batteries to photosynthesis. In a redox reaction, one species undergoes oxidation by losing electrons, while another undergoes reduction by gaining electrons.

Understanding redox reactions is crucial because it helps explain how certain chemical changes occur. For example, consider the reaction where sodium metal reacts with fluorine gas to form sodium fluoride. In this process, sodium atoms lose electrons (are oxidized) and fluorine atoms gain electrons (are reduced). The ability to identify which species is oxidized and which is reduced is a vital skill in chemistry.

Chemical Equation Balancing

Balancing chemical equations is a critical skill in chemistry that ensures the law of conservation of mass is upheld. This implies that the number of atoms for each element must be the same on both sides of the reaction. When writing a balanced chemical equation, we must adjust the coefficients (the numbers placed before compounds) to achieve this balance.

Take the reaction between sodium and fluorine to produce sodium fluoride. Initially, you might write it as Na + F₂ → NaF. However, this isn't balanced because there are two fluorine atoms on the reactant side, but only one fluorine in the product. By assessing the oxidation states and ensuring electron transfer is accounted for, it becomes clear we need two sodium atoms to balance the two electrons needed by the fluorine molecule – resulting in the balanced equation 2 Na + F₂ → 2 NaF.

Electron Transfer in Reactions

Electron transfer is the essence of redox reactions. It's the movement of electrons from one atom or molecule (the reductant) to another (the oxidant). This transfer of electrons is what changes the oxidation states of the atoms involved and drives the reaction forward.

In the context of our example reaction between sodium and fluorine, the sodium atoms each lose one electron, and these electrons are gained by the fluorine atoms, transforming them into fluoride ions. To illustrate, the sodium starts with an oxidation state of +1 and ends at 0 after losing an electron, while each fluorine atom starts at 0 and gains an electron to reach an oxidation state of -1. This interchange highlights the significance of electron transfer and how it correlates with the oxidation states of the involved elements.