chem

Predict the chemical formula for the ionic compound formed by the elements K and S

K₂S

How many core electrons does an atom of beryllium (Be) contain?

2. - Beryllium (Be) has four electrons and an electron configuration of 1s2 2s2. The electrons in the 1st shell are in the core and the electrons in the outer shell are valence electrons.

Predict the chemical formula for the ionic compound formed by NH₄⁺ and PO₄³⁻

(NH₄)₃PO₄

Recall that a group of elements on the periodic table represents a column of elements with similar chemical properties. What is the number (1-18) of the halogen group?

17

Write the complete ground-state electron configuration of Al³⁺.

1s²2s²2p⁶

Which of the following is a main group element?

Bismuth - The main group elements are elements that belong to the s and p blocks of the periodic table.

Which of the following radii comparisons is correct? A. N3- < N B. Ti4+ > Ti3+ C. In3+ < In+ D. C4+ > C4- E. As3- < As3+

C. In³⁺ < In⁺ - Cations are always smaller than the neutral atom from which it is derived. Anions are always larger than the neutral atom from which it is derived. Therefore, the smaller ion in a pair will be the one with fewer electrons.

Write the chemical formula for copper(I) hydroxide

CuOH

Predict the chemical formula for the ionic compound formed by Cu²⁺ and P³⁻

Cu₃P₂

Rank the following atoms in order of increasing first ionization energies (i.e., lowest to highest): Rb, F, Mg, B, N.

D) Rb < Mg < B < N < F - In general, first ionization energy decreases down a group and increases across a period.

Predict the chemical formula for the ionic compound formed by Fe³⁺ and O²⁻

Fe₂O₃

Write the chemical formula for ammonium hydroxide

NH₄OH

What type of bonding is present in SrCl₂?

ionic only

Ions are described as ________ if they have the same number of electrons.

isoelectronic

Provide the correct IUPAC name for MoCl₄.

molybdenum(IV) chloride

Write the complete ground-state electron configuration of O²⁻.

1s²2s²2p⁶

Write the complete ground-state electron configuration of Ca²⁺.

1s²2s²2p⁶3s²3p⁶

Write the complete ground-state electron configuration of Cl⁻.

1s²2s²2p⁶3s²3p⁶

The principal quantum number refers to the size and energy level of the outer orbital. The principal quantum number for Li is _____, whereas the principal quantum number for Fr is _______.

2; 7 -The principal quantum number is the shell number. This number increases in increments of 1 from the top to the bottom of a group.

Calculate the effective nuclear charge on a valence electron in a sulfur atom.

6 - The effective nuclear charge is the net charge that an electron experiences. An estimate of the effective nuclear charge (Zeff) can be calculated from Zeff=Z−S, where Z is the atomic number and S is the number of shielding electrons. - Sulfur has an atomic number of 16. There are 16 protons and 16 electrons in a sulfur atom. Sulfur has 6 valence electrons and 10 shielding electrons. Therefore, electrons in the valence shell will experience an effective nuclear charge of 6+.

Which of the following does NOT describe the element bromine (Br)?

A metalloid - Bromine (Br) is in group 7A (17) making it a halogen. This meas it is a main group element as well as a nonmetal.

Rank the following atoms in order of decreasing size (i.e., largest to smallest): Rb, F, Mg, B, N.

A) Rb > Mg > B > N > F - In general, atomic radius decreases across a period and increases down a group.

What element is theoretically the largest of all on the periodic table? A. Francium (Fr) B. Helium (He) C. Hydrogen (H) D. Lead (Pb) E. Radon (Rn)

A. Francium (Fr) - Atomic radius increases as you move down the periodic table and to the left. Francium is the furthest down and to the left of this group, would be predicted to be the largest element.

Which of the following ranks these isoelectronic species in order of increasing atomic radii?

Al³⁺ < Mg²⁺ < Ne < F⁻ < O²⁻ - In a series of isoelectronic ions, cations are smaller than anions. The larger the positive charge, the smaller the radius. The larger the negative charge, the larger the radius. A neutral atom is in the middle.

An atom has nine protons and ten electrons. This makes it:

An ion.

Choose the best explanation for why the atomic radius increases down a group on the periodic table.

As the number of energy levels (n) increases, there is a greater distance between the nucleus and the outermost orbital (radius).

Which of the following atom(s) below has/have five valence electrons? A. C B. N C. O D. F E. All of the above

B. N - Elements in group 15 have 5 valence electrons, including: N, P, As, Sb, Bi, Mc

Consider the atoms P, Br, and Ba. Which atom would have the largest atomic radius?

Ba - From right to left in the Periodic Table in the same period and as you move up in the Periodic Table, the size of a neutral atom decreases.

What is the formula for an ionic compound containing Ba²⁺ ions and Cl⁻ ions?

BaCl₂ - Two ions of chlorine are needed to balance out the positive charge on the barium ion.

Consider the atoms P, Br, and Ba. Which atom would have the greatest electron affinity?

Br - Electron affinity increases as you move from left to right on the Periodic Table, excluding the noble gases which do not want to gain electrons. Bromine (Br) has the highest electron affinity.

Which of the following is best classified as a covalent (molecular) compound?

CCl₄

Road salt is primarily calcium chloride. Write the chemical formula for calcium chloride.

CaCl₂

Which of the following is not a property affected by the effective nuclear charge, Zeff?

Color. Effective nuclear charge, Zeff, affects ionization energy, electron affinity, and atomic radius.

Based on their positions in the periodic table, which of the following bonds is the most polar? A.) C - O B.) C - N C.) C - B D.) C - F

D) C - F - Polar bonds occur between two nonmetals and have a difference in electronegativities of the atoms. The further apart two atoms are in the same period, the greater the polarity of the bond.

Which of the following is true concerning successive ionizations of an atom and its ions? A. Each successive ionization requires less energy to achieve B. All ionizations require the same amount of energy C. The amount of energy required to achieve a successive ionization doubles with each electron removed D. Each successive ionization requires increasing amounts of energy E. The first two ionizations are endothermic but each ionization afterwards is exothermic.

D) Each successive ionization requires increasing amounts of energy.

Considering periodic trends, valence electrons in which of the following atoms experience the greatest effective nuclear charge (Zeff)? A. Cl B. C C. F D. Ne E. B

D. Ne The Zeff increases from left to right in the periodic table

The energy released in the reaction: F(g) + e⁻ → F⁻(g) is known as the...

Electron affinity - The electron affinity is the change in energy when an electron is added to a neutral gaseous atom to form an ion.

Which of the following is a halogen?

Iodine - The halogens are found in group 17 and include F, Cl, Br, I, At, Ts

Classify the following compounds as ionic or covalent (molecular): KCl, CrCl₃, Cl₂O.

Ionic, ionic, covalent. - Ionic bonds occur between a metal and a nonmetal. Covalent bonds occur between two nonmetals.

Which periodic trend quantifies the amount of energy required to remove an electron from a neutral, gaseous atom?

Ionization energy

Which of the following is most likely to form a +2 ion?

Mg. - Elements in group 2 tend to form a +2 ion by losing its two valence electrons

Which of the following compounds contains a polyatomic ion?

MgCO₃ - A polyatomic ion is composed of multiple covalently bonded atoms. CO3^2− is a polyatomic ion composed of a carbon atom and three oxygen atoms.

Which of the following compounds does not contain a polyatomic ion?

NO₂ - is a covalent compound. There are no ions present in this molecule.

Which of the following compounds contain an ionic bond?

Na₃PO₄ - Sodium phosphate is a sodium salt and has ionic bonds between sodium and the phosphate ions.

Which of the following series of isoelectronic ions (Mg²⁺, N³⁻, F⁻, Si⁴⁺) has the ionic radii in order of largest to smallest?

N³⁻ > F⁻ > Mg²⁺ > Si⁴⁺ - For isoelectronic species, anions will be larger than cations. Ions can be further ranked by considering their charges. The greater the negative charge, the larger the size. The greater the positive charge, the smaller the size.

Which of the following is most likely to make a -3 ion?

P - An element that contains 5 electrons in its outer shell (Group 15) will be likely to gain three electrons to form a -3 ion and fill its octet.

Write the chemical formula for diphosphorus pentabromide

P₂Br₅

Based on the positions of the following elements on the periodic table, which of them would you expect to form a 3+ cation?

Scandium loses one 3d electron and two 4s electrons to form the Sc3+ cation. Aluminum loses one 3p electron and two 3s electrons to form the Al3+ cation.

Quicklime, CaO, is an important substance used in making mortar. What kind of bonds are present in this compound?

The ionic bond in this compound forms between the Ca2+ cation and the O2− anion.

Which is true about one formula unit of CaBr₂?

There is 1 positive Ca ion and 2 negative Br ions. - Calcium forms a +2 ion and bromine forms a -1 ion. There is one positive Ca ion and two negative Br ions in one formula unit of CaBr2

Predict the chemical formula for the ionic compound formed by V³⁺ and NO₂⁻

V(NO₂)₃

Provide the correct IUPAC name for AlBr₃.

aluminum bromide

The atomic radii of the alkali metals (Group 1) and the alkaline earth metals (Group 2) are shown below. Define the trend for atomic radii in a group.

atomic radii increase from the top to the bottom of a group.

Given that halogens are found in group 17 on the periodic table, what is the halogen in period 3?

chlorine

Provide the correct IUPAC name for CrN.

chromium(III) nitride

What type of bonding is present in H₂O₂?

covalent only

When an atom loses an electron, its radius ________.

decreases

The trend towards smaller atomic radii as one moves to the right in a period is _____.

due to the effective nuclear charge increasing. - The trend toward smaller atomic radii as one moves to the right in a period is due to the effective nuclear charge increasing.

Halogens tend to form anions because

gaining electrons will fill their octet faster than losing them.

Elements that are most similar in their properties are found _____

in the same group.

When an atom gains an electron, its radius ________.

increases

Trademarked as Agene, NCl₃ was used to bleach flour in the early 20th century. Provide the correct IUPAC name for NCl₃.

nitrogen trichloride

In a polar covalent bond,

one atom in the bond must have higher electronegativity than the other atom.

Which group in the periodic table tends to have high electronegativity values?

the halogens

Effective nuclear charge, Zeff, is defined as

the true nuclear charge minus the charge that is shielded by electrons; effective nuclear charge, Zeff, is defined as the true nuclear charge minus the charge that is shielded by electrons.

In a covalent bond

two atoms share valence electrons and those shared electrons form the chemical bond.

Consider the atoms P, Br, and Ba. Which atom would have the highest effective nuclear charge for its 1s electrons?

Ba - The effective nuclear charge can be estimated by calculating the difference between the atomic number and number of shielding electrons. In the 1s orbital for each atom, there would be no shielding electrons, so the highest atomic number would have the greatest effective nuclear charge. Barium (Ba) has the highest atomic number.

Which of the following is an alkaline earth metal?

Beryllium - The alkaline earth metals are found in group 2 and include Be, Mg, Ca, Sr, Ba, and Ra