
NSCI 100 NSCI100 Pre-Quiz 3 with Answers (UMUC)
NSCI 100 NSCI100 Pre-Quiz 3
- Which are older, the atoms in the body of an elderly person or those in the body of a baby?
- Does it make sense to say that a textbook is about 99.9 percent empty space?
- Since atoms are mostly empty space, why don't objects pass through one another?
- A beam of protons and a beam of neutrons of the same energy are both harmful to living tissue. The beam of neutrons, however, is less harmful. Why?
- Which contributes more to an atom's mass: electrons or protons? Which contributes more to an atom's size?
- If an atom has 43 electrons, 56 neutrons, and 43 protons, what is its approximate atomic mass? What is the name of this element?
- Oxygen atoms are used to make water molecules. Does this mean that oxygen, O2, and water, H2O, have similar properties?
- The concept of a chemical bond is ________.
- Which of the following has the greatest number of nonbonding pairs of electrons ?
- How is it possible for a neutral molecule, such as water, to form an ion?
- Which of the following elements will most likely not form an ion at all?
- Take money away from your bank account and the bank will show a negative credit. Take an electron away from an atom, however, and the atom shows up positive. Explain.
- Which of the following does not describe ionic compounds?
- Why are ores so valuable?
- Which of the following substances is pure?
- A friend argues that if mass were really conserved he would never need to refill his gas tank. What explanation do you offer your friend?
- The electric charge on all electrons
- If you strip electrons from an atom, the atom becomes a
- A difference between electric and gravitational forces is that electric forces include
- If two protons and two neutrons are removed from the nucleus of an oxygen atom, a nucleus of which element remains?
- Boron has primarily two isotopes, one with an atomic mass of 11 amu and another with an atomic mass of 10 amu. If the abundance of the boron atom with a mass of 11 amu is 18.9 percent and the abundance of the other isotope is 81.1 percent, what would be the average mass of the boron atom?
- If an element has 10 protons and 11 neutrons and 10 electrons, which expression correctly identifies the element?
- What does the following element description actually mean? - iron-57
- Helium, He, is a nonmetallic gas and the second element in the periodic table. Rather than being placed adjacent to hydrogen, H, however, helium is placed on the far right of the table because
- Does a shell have to contain electrons in order to exist?
- What is the valence shell?
- Is it at all possible for a hydrogen nucleus to emit an alpha particle?
- Which of the following statements about radiation is true?
- Which of the following emits more radiation?
- Which of the following statements best describes a critical mass?
- Oxygen atoms are used to make water molecules. Does this mean that oxygen, O2, and water, H2O, have similar properties?
- Many of the macroscopic properties of a compound depend on ________.
- Which of the following elements has six valence electrons?
- Why is it so easy for a magnesium atom to lose two electrons?
- Which of the following would be a negative ion with a single charge?
- Is an ionic compound an example of a chemical compound, or is a chemical compound an example of an ionic compound?
- What it the main difference between an ionic and a covalent bond?
- Which of the following statements is untrue?
- Atoms of metallic elements can form ionic bonds, but they are not very good at forming covalent bonds. Why?
- Which of the following is the strongest?
- What is the difference between a compound and a mixture?
- A combination of two or more substances in which they no longer retain their chemical properties is called a(n) ________.
- Why can't the elements of a compound be separated from one another by physical means?
- Classify the following as element, compound, or mixture, and justify your classifications: table salt, stainless steel, table sugar, aluminum, ice.
- Which has the most atoms?