TASK DEFINITION: You are given a sentence and your task is to generate another sentence that supports the given input.
PROBLEM: Reversible reactions are symbolized in chemical equations by a double-headed arrow, but the standard remains to call the materials on the left the reactants and the materials on the right the products.

SOLUTION: Reversible reactions are indicated by opposite-headed kinds of arrows.

PROBLEM: 1.3 Extinctions in the fossil record There are generally recognised to be five major extinction events in Earth s history, with resultant massive global (predominantly marine) losses of biodiversity.

SOLUTION: There have been five major massive extinctions since life began on earth.

PROBLEM: 1) In writing the formula or in naming the compound, the cation is listed first, and the anion next.

SOLUTION:
In naming ternary compounds, the cation is stated first.