Chapter 2 Practice Test Flashcards
Which of the three components of the atom has the smallest mass?
electron
Thomson’s electron-beam experiments determined _______.
the charge-to-mass ratio of an electron
Which of the following is not a postulate of Dalton’s atomic theory?
Elements are composed of many types of atoms
In his experiment, Millikan was able to determine the __________ of an electron. He then used the ratio discovered by Thomson to find the __________ of an electron.
charge; mass
Why were X-rays a necessary part of Millikan’s experiment?
The X-rays caused the oil drops to become charged.
Millikan determined the charge of an electron, which is _____________ .
1.60 × 10^−19 C
Why did it take 20 or so years after Rutherford’s gold-foil experiment for someone to finally prove the existence of neutrons?
Since neutrons had no charge, they could not be detected by electric or magnetic fields.
Rutherford used ________________ in his experiments to analyze the structure of an atom.
gold foil
Which of the three components of an atom are clustered in the nucleus?
neutrons and protons
What does a mass spectrometer measure?
the mass to charge ratio of an atom
A sample of an element is placed in a mass spectrometer. More than one signal is detected. What does this most likely indicate?
The atoms have varying numbers of neutrons
Carbon has 6 protons. A sample of carbon was placed in the mass spectrometer. A signal was detected at 12 and at 13. Which of the following statements is best explaination?
The sample contained two isotopes of carbon.
An atomic number represents the number of:
Protons
Isotopes are atoms of the same element with
the same number of protons and a varying number of neutrons.
On the periodic table, the atomic number given for an element
equals the number of protons in the element.