Question

which chemical equation correctly represents the reaction between sodium and chlorine to form sodium chloride? 2na + cl2 → nacl; na + cl2 → 2nacl; na + 2cl2 → 2nacl; 2na + 2cl2 → 2nacl. how does the periodic table help predict the outcome of chemical reactions? the periodic table is used to calculate the speed of chemical reactions.; the periodic table is used to measure the temperature of reactions.; the periodic table only shows the atomic mass of elements.; the periodic table can be used to predict how elements will react based on their group and period.

Explanation:

Step1: Balance the sodium - chlorine reaction

Sodium (Na) reacts with chlorine gas ($Cl_2$) to form sodium chloride (NaCl). The balanced chemical equation is $2Na+Cl_2
ightarrow 2NaCl$. We need 2 sodium atoms to react with 1 molecule of chlorine gas to form 2 molecules of sodium chloride to satisfy the law of conservation of mass.

Step2: Analyze the function of the periodic table

The periodic table arranges elements based on their atomic number. Elements in the same group have similar chemical properties due to the same number of valence electrons. The period indicates the number of electron - shells. This allows us to predict how elements will react based on their group and period.

Answer:

1. None of the given options for the first question is correct. The correct equation is $2Na + Cl_2

ightarrow2NaCl$.

1. D. The periodic table can be used to predict how elements will react based on their group and period.