Sample Answers E1 F07-3

Sample Answers E1 F07-3 - SampleExam1Answers.Biology210.

Info iconThis preview shows pages 1–2. Sign up to view the full content.

View Full Document Right Arrow Icon
Sample Exam 1 Answers. Biology 210. 1. If the number of protons are the same between two atoms, but the number of neutrons differ, these atoms are: a. different isotopes of the same element b. different elements c. in different valence states d. charged differently Answer: A. Protons and neutrons make up the nucleus of an atom. These paraticles have weigth and determine the atomic weight of an element. Atomic number (hence the name of the element) is determine solely by number of protons. Isotopes are atoms that have the same atomic number (same number of protons), but different atomic weights (different number of protons). Hydrogen ( 1 H) has one proton and no neutrons: atomic number 1 and atomic weight 1. Tritium (or hydrogen-3) is 3 H has one proton and two neutrons. These are isotopes of eachother. 2. Electrons exist only at fixed levels of potential energy. However, if an atom loses sufficient energy, a possible result is that: a. an electron may move to an electron shell farther out from the nucleus b. an electron may move to an electron shell closer to the nucleus c. the atom would become positively charged d. the atom would become negatively charged Answer: B. Electrons can only have certain defined levels of energy (quantum theory) and these are represented as shells of electrons around a nucleus. Inner shells have less enrgy than outer shells. More energy means that the electron can move further away from the nucleus that keeps attracting it. When an electron is excited by light energy, it moves to an orbit further from the nucleus. When the excited electron gives up energy (perhaps by releasing light), then it returns to its original orbit, the ground state, that is closer to the nucelus. 3. An ionic bond is one in which: a. electrons are removed from one atom and transferred to another atom so that the two atoms become oppositely charged b. outer-shell electrons are shared by two atoms so as to satisfactorily fill the outer electron shells of both c. outer shell electrons of one atom are transferred to the inner electron shells of another atom d. the inner-shell electrons of one atom are transferred to the outer shell of another atom
Background image of page 1

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Image of page 2
This is the end of the preview. Sign up to access the rest of the document.

Page1 / 6

Sample Answers E1 F07-3 - SampleExam1Answers.Biology210.

This preview shows document pages 1 - 2. Sign up to view the full document.

View Full Document Right Arrow Icon
Ask a homework question - tutors are online