Question

What is the difference between covalent bonds and ionic bonds?

Covalent bonds are formed between atoms to form molecules; ionic bonds are formed between atoms to form compounds.

Covalent bonds involve the sharing of pairs of electrons between atoms; ionic bonds involve the sharing of single electrons between atoms.

Covalent bonds involve the sharing of electrons between atoms; ionic bonds involve the sharing of protons between atoms.

Covalent bonds involve the sharing of electrons between atoms; ionic bonds involve the electrical attraction between atoms.

Atoms whose outer electron shells contain 8 electrons tend to

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form ions in aqueous solutions.

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form hydrogen bonds in aqueous solutions.

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be stable and chemically nonreactive, or inert.

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be both chemically inert and gaseous at room temperature.

Orange juice has a pH of 3 and Black coffee has a pH of 5 This means that:

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Orange juice has 100 times more H+ions than Black coffee

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Orange juice is less acidic than Black coffee

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Orange juice has 4 times more H+ions than Black coffee

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Black Coffee has 100 times more H+ions than Orange juice

Nitrogen (N) is much more electronegative than hydrogen (H). Which of the following statements is correct about the atoms in ammonia (NH3)?

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The nitrogen atom has a slight positive charge; each hydrogen atom has a slight negative charge.

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Each hydrogen atom has a partial positive charge; the nitrogen atom has a partial negative charge.

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Each hydrogen atom has a slight negative charge; the nitrogen atom has a strong positive charge.

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The nitrogen atom has a strong positive charge; each hydrogen atom has a strong positive charge.

Atomic number is best described as:

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the number of protons in atom

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the number of neutrons in atom

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the number of electrons in the outermost shell of atom

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only A and B

When two atoms are equally electronegative, they will interact to form

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hydrogen bonds.

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van der Waals interactions.

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polar covalent bonds.

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nonpolar covalent bonds.

The atomic number of neon is 10. Therefore, which of the following is most correct about an atom of neon?

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It has an atomic mass of 10 daltons.

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It has 8 electrons in its outer electron shell.

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It is inert.

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It has 8 electrons in its outer electron shell and it is inert.

About 25 of the 92 natural elements are known to be essential to life. Which four of these 25 elements make up approximately 96% of living matter?

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carbon, sodium, hydrogen, nitrogen

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carbon, oxygen, phosphorus, hydrogen

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carbon, hydrogen, nitrogen, oxygen

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oxygen, hydrogen, calcium, nitrogen

Which of the following is not considered to be a weak molecular interaction?

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an ionic bond in the presence of water

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a covalent bond

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a van der Waals interaction

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a hydrogen bond

Which statement is NOT true about the pH scale?

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pH has a balanced level of H+and OH-

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Anything below pH 7 is acidic and above pH7 is basic

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The scale indicates the relative concentrations of hydrogen and hydroxyl ions in a solution.

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all given statements are true

A covalent chemical bond is one in which

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outer-shell electrons of two atoms are shared so as to satisfactorily fill the outer electron shells of both atoms.

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protons and neutrons are shared by two atoms so as to satisfy the requirements of both atoms.

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outer-shell electrons of one atom are transferred to fill the inner electron shell of another atom.

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electrons are removed from one atom and transferred to another atom so that the two atoms become oppositely charged.

A covalent bond is likely to be polar when

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one of the atoms sharing electrons is much more electronegative than the other atom.

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one of the atoms has absorbed more energy than the other atom.

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oxygen is one of the two atoms sharing electrons.

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the two atoms sharing electrons are equally electronegative.

In what way are elements in the same column of the periodic table the same?

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They have the same number of electron shells.

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They have the same number of electrons in their valence shell.

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They have the same number of protons.

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They have the same number of neutrons

The nucleus of a nitrogen atom contains 7 neutrons and 7 protons. Which of the following is a correct statement concerning nitrogen?

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The nitrogen atom has a mass number of 14 and an atomic mass of 7 grams.

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The nitrogen atom has a mass number of approximately 7 daltons and an atomic mass of 14.

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The nitrogen atom has a mass number of 14 and an atomic number 7

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The nitrogen atom has a mass number of approximately 14 daltons and an atomic mass of 7.

Knowing just the atomic mass of an element allows inferences about which of the following ?

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the number of protons plus neutrons in the element

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the number of neutrons in the element

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the chemical properties of the element

the number of protons in the element

_______have identical molecular formulas but the atoms in each molecule are arranged differently?

organic

homomolecules

isomer

isotope

Which statement is NOT true about ionic bonds?

electrons are completely lost or gained in ion formation

one atom acts as an electron donor and another acts as an electron acceptor

a salt such as NaCl is formed by an ionic reaction

an ion has the same number of electrons as a non-ionic atom of the same element

Why is each element unique and different from other elements in chemical properties

Each element has a unique atomic mass.

Each element has a unique atomic weight.

Each element has a unique number of neutrons in its nucleus

Each element has a unique number of protons in its nucleus.

Which of the following explains most specifically the attraction of water molecules to one another?

hydrogen bond

ionic bond

nonpolar covalent bond

polar covalent bond

Which bond or interaction would be difficult to disrupt when compounds are put into water?

ionic bond

hydrogen bond

van der Waals interaction

covalent bond

What results from an unequal sharing of electrons between atoms?

a polar covalent bond

an ionic bond

a hydrogen bond

a nonpolar covalent bond

which of the following molecules contains the most polar covalent bond?

H2O

H2

CO2

O2

Two atoms appear to have the same mass number. These atoms

must have the same number of protons + neutrons.

must have the same atomic number.

must have the same chemical properties.

must have the same number of electrons.

Electrons exist only at fixed levels of potential energy. However, if an atom absorbs sufficient energy, a possible result is that

an electron may move to an electron shell closer to the nucleus.

an electron may move to an electron shell farther away from the nucleus.

the atom would become a positively charged ion, or cation, and become a radioactive isotope.

the atom may become a radioactive isotope.

How many electrons are involved in a triple covalent bond?

one

six

three

two

From its atomic number of 15, it is possible to predict that the phosphorus atom has

15 neutrons.

15 electrons.

15 protons and 15 electrons.

15 protons.

Atoms of an element react is most related to the

number of electrons in the outermost shell

number of neutrons in the nucleus

number of electrons in the innermost shell

size of the nucleus

Answer 1

Difference between covalent and Ionic bonds,

Covalent bonds involve the sharing of pairs of electrons between atoms; ionic bonds involve the sharing of single electrons between atoms.

Electrons of an atom is organized into shells. Each shell consists of sub-shells according to their size. There are 4 sub-shell type,  s,p,d and f.

s ,p,d,f sub-shells can hold 1,3, 5, 7 pairs of electrons respectively.

So each shell is made up of sub-shells in a combination of,

Shell 1 (K) s = 2 electrons

Shell 2(L) s+p= 2+6 =8 electrons

Shell 3(M) s+p+d = 2+6+10 = 18 electrons

Shell 4(N) s+p+d+f = 2+6+10+14 = 32 electrons

So an atom with 8 electrons at outer shell will fill s+p sub-shell and become stable.

Atom which contains 8 electrons at the outer shell tend to be stable and chemically nonreactive or inert.

Orange juice has pH of 3 and black coffee has pH of 5 means Orange juice has 100 times more H+ions than Black coffee.

pH is the potential of hydrogen. It is the negative logarithm of hydrogen ion concentration in a solution. Low pH means high acidity . pH 3 is 100 times acidic than pH 5.

Each hydrogen atom has a partial positive charge; the nitrogen atom has a partial negative charge.

Atomic number is best described as The number of Protons in atom.

When two atoms are equally electronegative, they will interact to form Nonpolar covalent bonds.

Because they have same electronegativity so they will share their valance electrons equally with each other. Thus forming Nonpolar covalent bond.

The atomic number of Neon is 10.. Therefore the most correct statement about Neon is It has 8 electrons at its outer electron shell and it is inert.

2 electrons at the K shell and 2+6=8 electrons at L shell.