Anewly discovered element, z, has two naturally occurring isotopes. 90.3 percent of the sample is an isotope with a mass of 267.8 u, and 9.7 percent of the sample is an isotope with a mass of 270.9 u. what is the weighted average atomic mass for this element? (2 points)

a)268.1 u

b)269.0 u

c)269.4 u

d)270.6 u

Pauling and lewis questioned the extreme definitions of bonds. they wondered if bonds might be described somewhere in between the two extremes (covalent and ionic). on the basis of experimental data, pauling confirmed that bonds could be ionic, covalent, and for those, in between, exhibit a degree of ionic character. he theorized that the major factor was how strongly the atoms in the bond attracted the electrons. pauling called this factor - the tendency of an atom to attract electrons in a bond.

Many bird species build nests in which they raise their offspring. one of these species is known as the magnolia warbler. breeding pairs of magnolia warblers build nests out of pieces of grass and twigs. the female warbler will then lay her eggs in the nest and sit on the eggs for a few weeks until they hatch. after the offspring have hatched, the female will continue to sit on the newborn chicks to keep them warm. both the male and the female bring food for the offspring to eat until the young are mature enough to find food on their own. which of these most likely describes why birds such as the magnolia warbler build nests in which to raise their offspring? a. nest building decreases the amount of energy used by the parent birds to raise their offspring to adulthood. b. nest building increases the probability that the offspring will survive and eventually produce offspring of their own. c. nest building decreases the amount of food that the offspring require the adult birds to provide. d. nest building increases the probability of the offspring being located by airborne predators.

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