GCHM Unit 2 Review

What elements are in ammonium magnesium phosphate, NH₄MgPO₄?

nitrogen, hydrgen, magnesium, phosphorus, oxygen

Which of the following is a characteristic of the modern periodic table?

The elements in each group have similar chemical properties.

The Group 8A (18) elements

are unreactive and are rarely found in combination with other elements.

Identify the metalloid in the following list.

arsenic

What is the symbol of the element in Period 5 and Group 7 A (17)?

I

Which of the following elements is a noble gas?

Krypton

The smallest particle of an element that retains the characteristics of the element is a(n)

atom.

The atomic number of an atom is equal to the number of

protons

The mass number of an atom can be calculated from

the number of protons plus neutrons.

The atomic mass of an element is equal to

its mass number.

Which of the following electron configurations is impossible?

1s2 2s4 2p6 3s2 3p3

What is the nuclear symbol for a radioactive isotope of copper with a mass number of 60?

60 / 29 Cu

Which of the following types of radiation has the highest energy?

gamma rays

Which of the following is suitable as a minimum shielding for beta particles?

gloves

The process in which a nucleus spontaneously breaks down by emitting radiation is known as

radioactive decay.

The nuclear reaction shown below is an example of what type of process?

224/90 Th —> 220/88 + 4/2 He

alpha decay

The nuclear reaction is an example of 

126/50 Sn —> 126/51 Sb + ?

beta decay.

What is missing in the nuclear reaction shown below?

10/5 B + 4/2 He —> ? + 1/0 n

13/7 N

One symptom of mild radiation sickness is

a lowered white cell count.

When an atom of uranium-235 is bombarded with neutrons, it splits into smaller nuclei and produces a great amount of energy. This nuclear process is called

fission.

In the Sun, nuclei of hydrogen combine to form a larger nucleus and release a great amount of energy. The process is known as

fusion

Valence electrons are electrons located

in the outermost energy level of an atom.

The octet rule indicates that

atoms lose, gain, or share valence electrons to have elght valence electrons.

What is the ionic charge of an ion with 12 protons and 10 electrons?

2+

Elements in group 1A (1) of the periodic table form ions with a charge of

1+

Which of the following is the correct electron-dot structure for carbon?

One dot on the top, left, bottom, and right of carbon’s symbol

In a covalently bonded molecule, the number of electrons that an atom shares with others is usually equal to the number of electrons

needed to give it a stable electron configuration.

Double and triple bonds form because

single covalent bonds do not give all of the atoms in the molecule an octet of electrons.

The ability of an atom to attract the shared electrons in a covalent bond is its

electronegativity.

The VSEPR theory allows us to determine the most favorable

three-dimensional shape of a molecule.