When moving across a period from left to right in the periodic table, excluding transition elements, which trend occurs?(1 point) Valence electrons increase by one.

Valence electrons decrease by one.

The energy levels increase by one.

The energy levels decrease by one.

Suppose that a comet that was seen in 563 a.d. by chinese astronomers was spotted again in year 1951. assume the time between observations is the period of the comet and take its eccentricity as 0.986. what are (a) the semimajor axis of the comet's orbit and (b) its greatest distance from the sun?

Which of the following is not a part of the respiratory system? a. pharynx b. trachea c. pancreas d. larynx

Alfred pushes on a heavy box, but cannot move it. the box has a lot of inertia motion friction gravity