What is the hardest part of the periodic table?

What rule is used to determine how many covalent bonds an element can form? a. the number of covalent bonds is equal to six c the number of covalent bonds is equal to five minus the group number plus the group number b. the number of covalent bonds is equal to eight d. none of the above minus the group number select the best answer from the choices provided

Arrange the elements in order of increasing electronegativity. use the periodic table to you arrange the elements. p o k mg

Which of these is a density dependent factor? a. epidemic b. earthquake c. drought d. hurricane