PHY-118 ch.12
If a neutral element has 8 neutrons and 7 electrons, which expression correctly identifies the element?
15/7 N
If an element has 9 protons and 10 neutrons and 9 electrons, which expression correctly identifies the element?
19/9 F
If a neutral element has the following chemical notation, how many electrons does it have? fluorine-19
9
If a neutral element has the following chemical symbol, how many electrons does it have? 235 U 92
92
What is the approximate mass of a carbon atom in atomic mass units (amu)? How about a carbon dioxide molecule?
A carbon atom has a mass of about 12 amu. Carbon dioxide would then have a mass of 44 amu.
What does the following element description actually mean? 238 U 92
A uranium atom with 92 protons and 146 neutrons.
Which color of light comes from the higher energy transition, red or blue?
Blue is a higher frequency and therefore corresponds to higher energy level transition.
Which of the following elements are in the same group as silicon (Si)?
C
What are metalloids?
Elements that have some properties like metals and some like nonmetals.
What is the main tenet of Plank's quantum hypothesis?
Energy comes in discrete packets of a certain minimum size.
Which element has the atomic number 9?
F
How is it possible to deduce the identity of an element from its electron configuration?
If the atom is electrically neutral, the number of electrons corresponds to the atom's atomic number.
Where did the atoms that make up a newborn baby originate?
In the explosions of ancient stars.
What is the valence shell?
It is the outermost shell of electrons in an atom.
An element has two different isotopes: one that weighs 65 amu and another that weighs 67 amu. If the average atomic mass of all the isotopes is 66.5 amu, what can be said about the relative abundance of the isotopes?
The isotope with the mass of 67 is more abundant than the isotope with the mass of 65.
Evidence for the existence of neutrons did not come until many years after the discoveries of the electrons and the proton. Give as possible explanation.
The neutron lacks an electrical charge.
How do we account for the great variety of substances in the world?
There are many possible combinations of atoms.
Why can't we see atoms?
We see with light energy and the wavelength is larger than the object and so it is not reflected.
How does the wave model of electrons orbiting the nucleus account for the fact that the electrons can have only discrete energy values?
When an electron wave is confined, it is reinforced only at particular frequencies.
How would you describe light generated by heating pure elements if it was observed through a prism or spectroscope?
You would see a series of very sharp lines of emitted light.
Does a shell have to contain electrons in order to exist?
a.) A shell is just a region of space which may or may not contain electrons. b.) A shell is a form of energy that requires electrons in order to exist. c.) A shell is just a conceptual model, hence, it doesn't really exist with or without the electron. d.) Two of the above are reasonable answers. Answer: D
The following statement describes which subatomic particle best? it is a nucleon.
a.) an electron b.) a proton c.) a neutron d.) A and B e.) B and C Answer: E
Does a shell have to contain electrons in order to exist?
a.)A shell is just a conceptual model, hence, it doesn't really exist with or without the electron. b.)A shell is a form of energy that requires electrons in order to exist. c.)A shell is just a region of space which may or may not contain electrons. d.)Two of the above are reasonable answers. Answer: D
What do the components of a conceptual model have in common?
a.)All components interact with each other. b.)Each component must correlate with a corresponding component of a physical model. c.)The components have nothing in common. This is what differentiates a conceptual model from a physical model. d.)All components are mutually independent of each other. Answer: A
What happens to the properties of elements across any period of the periodic table?
a.)The properties of the elements gradually change across any period of the periodic table. b.)The elements get much larger in size because of the addition of more protons and electrons. c.)The elements tend to become more metallic in nature since they are increasing in atomic number. d.)All of the above are true. Answer: A
The following statement describes which subatomic particle best? It is electrically charged.
a.)an electron b.)a proton c.)a neutron d.)A and B e.)B and C Answer: D
Which of the following is a metalloid?
antimony (atomic no. = 51)
Elements that are in the same ________ have a tendency to have very similar chemical properties due to periodic trends.
group
Which of the following is not the name of a chemical family?
heavy metals.
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.
helium is most similar to other group 18 elements.
Would you use a physical model or a conceptual model to describe the following: a gold coin, dollar bill, car engine, air pollution, virus, spread of sexually transmitted disease?
physical model-gold coin, car engine, virus; conceptual model-air pollution, spread of sexually transmitted disease; dollar bill, which could represent wealth, may well be described by either model.
Which of these is not a metal?
selenium (atomic no. = 34)
Which of the following elements is a transition metal?
silver (Ag)
Which of the following is most easily understood to be quantized?
the number of eggs in an egg carton
According to the shell model, which electrons play the most significant role in determining the properties of an atom?
those in the outermost shell
Which of the following elements is a halogen?
Chlorine (CI)
How can a hydrogen atom, which has only one electron, have so many spectral lines?
One electron can be boosted to many different energy levels.
Which atom is largest?
Rb