Atomic Structure 10-22-13

Which statement identifies the element arsenic? 1.Arsenic has an atomic number of 33 2.Arsenic has a melting point of 84K 2.An atom of arsenic in the ground state has eight valence electrons 4.An atom of arsenic in the ground state has a radius of 146 pm

1. arsenic has an atomic number of 33

An atom is electrically neutral because 1. number of protons equals number of electrons 2. number of protons equals number of neutrons 3. ratio of number of neutrons to the number of electrons is 1:1 4. ratio of the number of protons 2:1

1. number of protons equals number of electrons

Which set of symbols represents atoms with valence electrons in the same electron shell? 1. Ba,Br, Bi 2. Sr, Sn, I 3.O,S,Te 4.Mn,Hg, Cu

2. Sr, Sn, I

What are the characteristics of a neutron? 1. It has no charge and no mass 2.It has no charge and a mass of 1 u 3.It has a charge ⁺1 and no mass 4. It has a charge of ⁺1 and a mass of 1 u

2.It has no charge and a mass of 1 u

Subatomic particles can usually pass undeflected through an atom because the volume of an atom is composed of 1. an uncharged nucleus 2.largely empty space 3.neutrons 4. protons

2.largely empty space

An atom of potassium -37 and atom of potassium -42 differ in their total number of 1. electrons 2.neutrons 3.protons 4. positrons

2.neutrons

The most common isotope of chromium has a mass number of 52 . Which notation represents a different isotope of chromium? (1) ₅₂ ₂₄Cr (2) ⁵⁴ ₂₄Cr (3) ²⁴ ₅₂Cr (4) ²⁴ ₅₄Cr

(2) ⁵⁴ ₂₄Cr

32. In the formula X2O5, the symbol X could represent an element in Group (1)1 (2) 2 (3) 15 (4) 18

(3) 15

Which statement describes the relative energy of the electrons in the shells of a calcium atom? (1) An electron in the first shell has more energy than an electron in the second shell. (2) An electron in the first shell has the same amount of energy as an electron in the second shell. (3) An electron in the third shell has more energy than an electron in the second shell. (4) An electron in the third shell has less energy than an electron in the second shell.

(3) An electron in the third shell has more energy than an electron in the second shell.

If an element, X, can form an oxide that has the formula If an element, X, can form an oxide that has theformula X2O3, then element X would most likely be located on the Periodic Table in the same group as (1) Ba (2) Cd (3) In (4) Na

(3) In

Which of these elements has an atom with the most stable outer electron configuration? 1. Ne 2.Cl 3.Ca 4.Na

1.Ne

Which statement explains why sulfur is classified as a Group 16 element? 1.a sulfur atom has 6 valence electrons 2. a sulfur atom has 16 neutrons 3. Sulfur is a yellow solid at STP 4. Sulfur reacts with most metals

1.a sulfur atom has 6 valence electrons

The atomic mass of an element is the weighted average of the... ? 1)number of protons in the isotopes of that element 2)number of neutrons in the isotopes of that element 3)atomic numbers of the naturally occurring isotopes of that element 4)atomic masses of the naturally occurring isotopes of that element

3)atomic masses of the naturally occurring isotopes of that element

A sample composed only o atoms having the same atomic number is classified as. 1. compound 2. a solution 3. an element 4. an isomer

3. an element

What determines the order of placement of the elements on the modern Periodic Table? 1.atomic mass 2. the number of neutrons, only 3. atom number 4. the number of neutrons and protons

3. atom number

A student constructs a model for comparing the masses of subatomic particles. The student selects a small, metal sphere with which mass would be most appropriate to represent a proton? 1. 1 g 2. 1/2 g 3. 1/200 g 4. 2000 g

4. 2000 g

What is the structure of Krypton -85 atom? 1. 49 electrons, 49 protons, and 85 neutrons 2. 49 electrons, 49 protons, and 49 neutrons 3. 36 electrons, 36 protons, and 85 neutrons 4. 36 electrons, 36 protons, and 49 neutrons

4. 36 electrons, 36 protons, and 49 neutrons

Which statement concerning elements is true? 1. different elements must have different number of of isotopes 2. different elements must have different number of neutrons 3.all atoms of a given element must have the same mass number 4. All atoms of a given element must have the same atomic number.

4. All atoms of a given element must have the same atomic number.

According to the electron cloud model of the atom, an orbital is a 1. circular path traveled by an electron around the nucleus. 2. spiral path traveled by an electron toward the nucleus 3.region of the most probable proton location 4. region of the most probable electron location

4. region of the most probable electron location

A 100.00-gram sample of naturally occurring boron contains 19.78 grams of boron-10 (atomic mass = 10.01 atomic mass units) an d 80.22 grams of boron- 11 (atomic mass = 11.01 atomic mass units). Which numerical setup can be used to determine t he atomic mass of naturall y occurring boron? A. (0.1978)(10.01) + (0.8022)(11.01) B. (0.8022)(10.01) + (0.1978)(11.01) C. (0.1978)(10.01)/(0.8022)(11.01) D. (0.8022)(10.01)/(0.1978)(11.01)

A. (0.1978)(10.01) + (0.8022)(11.01)

In which group of the Periodic Table do most of the elements exhibit both a positive and negative oxidation states? A. 17 B. 2 C.12 D. 7

A. 17

As the elements in Group 17 are considered in order of increasing atomic number, the chemical reactivity of each successive element a. decreases b. increases c. remains the same

a. decreases

The mass of 12 protons is approximately equal to a. 1 atomic mass unit b. 12 atomic mass units c. the mass of 1 electron d. the mass of 12 electrons

b. 12 atomic mass units

The table below gives information about the nucleus of each of four atoms atom number of protons number of neutrons A 6 6 D 6 7 E 7 7 G 7 8 How many different elements are represented in the nuclei in the table? a.1 b.2 c.15 d.18

b.2