General Physical Science Exam #3

If a neutral atom gains two electrons, what is the electrical charge of the atom?

-2

If a neutral element has 8 neutrons and 7 electrons, which expression correctly identifies the element?

15 -- N 7

If an element has 15 protons and 16 neutrons and 15 electrons, what is the mass number of the element?

31

How many atoms of Oxygen (O) are in H3OCIO4?

5

What is a rem?

A rem is a unit for measuring radiation exposure

Which of the following is a positive ion?

All of the above

What is the name of the following compound? CO2

Carbon dioxide

A chemical change involves the formation of elements?

Chemical change because the atoms are connected differently

Is the following transformation representative of a physical change or a chemical change?

Chemical change because the atoms are connected differently

An element is best described as a material

Consisting of only one type of atom

Which of the following would be considered applied research?

Determining the lightest and strongest metal to be used for an airplane wing

Which of the following is not property of metal?

Does not conduct heat well

How do the electron-dot structures of elements in the same group in the periodic table compare with one another?

Elements of the same group have the same number of valence electrons

Radioactivity is a tendency for an element or a material to

Emit radiation

People who work around radio activity wear film badges to monitor the amount of radiation that reaches their bodies. These badges consist of small pieces of photographic film enclosed in a light-proof wrapper. What kind of radiation do these devices monitor?

Gamma radiation

Which of the following is not a chemical change?

Grass growing

The concept of a chemical bond is

How two or more atoms are held together

What does the following element description actually mean? iron-57

Iron with a mass number of 57

Why is it better to recycle metals than to mine more?

Mining is less expensive than recycling but not environmentally friendly

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.

Neutral atoms contain identically charged but oppositely signed protons and electrons. Removing one of the negative electrons results in an excess of positively charged protons.

Which of the following best describes ionic bonding?

One atom giving up some of its electrons to another atom

If a material has a half-life of 24 hours, how long do you have to wait until the amount of radioisotope is 1/4 its original amount?

Practically forever, but it may be safe by then.

Which contributes more to an atom's mass: electrons or protons? Which contributes more to an atom's size?

Protons contribute more to an atom's mass while electrons contribute more to its size.

Which of the following statements about radiation is true?

Radiation can be a useful tool. Like fire, it is only dangerous when misused.

Which of the following provides the minimum amount of protection you need to block the following form of radiation? Alpha

Suntan lotion

A friend produces a Geiger counter to check the local background radiation. It ticks. Another friend, who normally fears most that which is understood least, makes an effort to keep away from the region of the Geiger counter and looks to you for advice. What do you say?

The Geiger counter is detecting naturally occurring radiation from your body

Why are the atomic masses listed in the periodic table not whole numbers?

The atomic masses are average atomic masses

The following image describes what type of charge?

a chemical change apart everywhere and then black dots on all the other dots

The following image describes which type of change?

a physical change bunched together and then all apart

You are given three radioactive samples (a, b, y) and can only dispose one. The other two you must keep, one in your hands, and the other in your pocket. How would you minimize your exposure risk?

keep (a) in hand, (b) in pocket, and dispose of (y)

In what phase of matter are the particles no longer moving

none of the above

Which of the following is a negative ion?

o -2

A cat strolls across your backyard. An hour later, a dog with its nose to the ground follows the trail of the cat. Explain what is going on from a molecular point of view.

The dog is smelling molecules from the cat.

Since atoms are mostly empty space, why don't objects pass through one another?

The electrons on the atoms repel other electrons on other atoms when they get close.

Evidence for the existence of neutrons did not come until many years after the discoveries of the electron and the proton. Give a possible explanation.

The neutron lacks an electrical charge

How can a half-life be used to tell the age of a sample?

The ratio between the radioactive form and stable form varies regularly with time.

What is one role unpaired valance electrons?

They take part in the formation of different types of bonds

Which of the following provides the minimum amount of protection you need to block the following form of radiation? Beta

Thick leather

What is the name of the following compound? SF3

Trifluorosulphide

In what sense can you truthfully say that you are a part of every person around you?

We are continually exchanging our atoms