V. Indiquen el número de protones y electrones en los siguientes iones. •Un ion que tiene una masa atómica de 35 uma, 18 neutrones y una carga (-1)
•Un ion que tiene una masa atómica de 27uma, 14 neutrones y una carga (3+)
•Un ion que tiene una masa atómica de 36 uma, 19 neutrones y una carga (-1)
•Un ion que tiene una masa atómica de 39 uma, 20 neutrones y una carga (1+)
•Un ion que tiene una masa atómica de 24 uma, 12 neutrones y una carga (2+)

substituting a hydrogen atom with a halogen in a hydrocarbon:

- the single bond remains single. a is wrong.

- the bond with hydrogen is as strong as with a halogen. c is wrong

- a hydrocarbon is saturated if there is no double bond. we do not know that so d is wrong.

- carbon will always have four valence electrons. e is wrong.

by elimination, the correct answer is b. the boiling point of the new compound increases.

chemical changes occur when a substance combines with another to form a new substance, called chemical synthesis or, alternatively, chemical decomposition into two or more different substances. these processes are called chemical reactions and, in general, are not reversible except by further chemical reactions. some reactions produce heat and are called exothermic reactions and others may require heat to enable the reaction to occur, which are called endothermic reactions. understanding chemical changes is a major part of the science of chemistry.