1. Which two elements are mainly found in the inner and outer core?
A. Fe and Ni
B. Fe and Si
C. Ni and Si
D. Ni and C

2. Why is the inner core solid?
A. Even though it is as hot as the surface of the Sun, it has immense pressure upon it
B. Iron and Nickel are only solid
C. Nickel is not dense
D. It is made up mostly of granite and basalt.

the enthalpy of formation of water is given as -285.8kj/mol, which states that the enthalpy of formation is negative.

negative enthalpy of formation indicates that the heat is released during the reaction process. the heat is released from reaction to the surroundings the enthalpy is expressed with a negative sign with the energy given out in the reaction process.

the formation of water takes place by giving out heat which is -285.8 kj/mol.

answer:

technetium is the most reactive. this is followed by silver. the least reactive out of these three elements is strontium.