Atomic Structure

Choose the correct balanced equation for the following reaction. C8H18 + O2 --> CO2 + H2O

2 C8H18 + 25 O2 --> 16 CO2 + 18 H2O

The mass number of an atom is 15, and its atomic number is 7. The atom probably has...

8 neutrons in the nucleus because the mass number is the number of protons plus neutrons.

Dr. Jones says an atom has 3 electrons in the first shell and four electrons in the second shell. Someone should tell Dr. Jones that ... the second shell can't have 4 electrons. the first shell shouldn't have 3 electrons. the second shell should have 8 electrons. no shell can hold more than 2 electrons. the first shell must fill before the second shell can have electrons.

the first shell shouldn't have 3 electrons.

A solution is aqueous if ...

water is the solvent.

An atom has 8 protons, 8 neutrons, and 8 electrons. Another isotope of the same element might have ...

10 neutrons. Isotopes have the same number of protons; different numbers of neutrons.

To fill the valence shell, an electrically neutral, unbonded atom with atomic number 8 must add ...

2 electrons because The neutral atom has 8 electrons. Two electrons fill the first shell, and 6 go into the second (valence) shell. Two more electrons would fill the valence shell.

An atom's atomic number is 7. Its valence is most likely ...

3 because The neutral atom has 7 electrons. Two electrons fill the first shell, and 5 go into the second (valence) shell. The atom needs 3 more electrons to fill the valence shell.

In molecules, C, H, O, and N atoms usually make __, __, __, and __ bonds respectively. 3, 2, 4, 2 2, 1, 3, 4 3, 2, 1, 4 4, 1, 3, 2 4, 1, 2, 3

4, 1, 2, 3.

The atom has a vacancy in its inner shell; an electron has moved to the outer (valence) shell. The result is an unstable excited state. What will be the fate of the electron?

An electron will move back to the inner shell, restoring the ground state as the atom gives off energy.

Choose the appropriate balanced equation for the following chemical reaction. C6H6 + H2 --> C6H12

C6H6 + 3 H2 --> C6H12;

An atom has 6 electrons, 6 protons, and 6 neutrons. You can tell that this atom belongs to the element _____ because _____________________.

C; it has 6 protons.

Which statement is true of atoms? Electrons determine the atom's size. Protons repel electrons. Protons attract other protons. Most of an atom's volume is filled with matter. All of the above.

Electrons determine the atom's size. With electrons on the surface, atoms repel one another when they come too close. Thus, electrons determine the space that an atom occupies.

Which statement about the following reaction is true? 4 Fe + 3 O2 --.> 2 Fe2O3 The reaction is not balanced. Four grams of Fe reacts with 3 grams of O2 to form 2 grams of Fe2O3. Fe2O3 is the reactant in this reaction. Four atoms of Fe react with 3 molecules of O2 to form 2 molecules of Fe2O3 None of the above.

Four atoms of Fe react with 3 molecules of O2 to form 2 molecules of Fe2O3. You identified the reactants as Fe and O and the product as Fe2O3. You also knew that the coefficients in the equation correspond to the number of atoms or molecules that take part in the reaction

Which statement is true of the energy levels of electrons in shells? Electrons must lose energy to move from the first to the second shell. The valence shell has higher energy than other occupied shells. All the electrons in an atom have similar amounts of energy. All of the above. None of the above.

The valence shell has higher energy than other occupied shells. The outer occupied shell is the valence shell, and outer shells hold electrons at higher energy than inner shells.

Two atoms always represent the same element if they have ... the same number of electrons. the same mass number. the same number of shells. the same number of protons. the same number of particles in the nucleus.

the same number of protons.