Question 1: which of the following statement is false about conjugated systems?

a. a conjugated system is more stable than an unconjugated system.

b. the s-trans isomer is favored over the s-cis isomer.

c. a conjugated system has multiple resonance structures.

d. a conjugated system can only contain two alkenes

question 2: which statement concerning alkenes is false?

a. a trans alkene releases less heat upon hydrogenation than a cis alkene.

b. a cumulated diene is less stable than an isolated diene.

c. multiple products can always form when treated a conjugated diene with hbr.

d. conjugated systems arise only between sp2-hybridized atoms.

e. conjugated double bonds involve unhybridized p-orbitals aligned with each other

A conjugated system can only contain two alkenes: False

B. A cumulated diene is less stable than an isolated diene.

False

Explanation:

A. A conjugated system is more stable than an unconjugated system.: True

Due to resonance a conjugated system is more stable.

B. The s-trans isomer is favored over the s-cis isomer.: True

Due to repulsion in s-cis isomer they are less stable.

C. A conjugated system has multiple resonance structures. True

This is the reason they are stable.

D. A conjugated system can only contain two alkenes: False

A conjugated system may have may alternate double and triple bonds.

2) A trans alkene releases less heat upon hydrogenation than a cis alkene.

True

Trans alkenes are more stable than cis alkene. Thus heat of hydrogenation of trans alkene is less than cis alkene.

B. A cumulated diene is less stable than an isolated diene.

False

C. Multiple products can always form when treated a conjugated diene with HBr.  True

There can be 1,2 or 1,4 addition

D. Conjugated systems arise only between sp2-hybridized atoms.

True

Conjugation allows resonance which is possible in sp2 systems

E. Conjugated double bonds involve unhybridized p-orbitals aligned with each other

True

The double bond is formed as pi bond due to side ways overlapping of unhybridized p orbitals

explanation:

let the different atoms be x and y. each with four protons and same mass will be represented as follows.

mass number is number of protons + number of neutrons.

            and  

since, it is given that one has a negative charge while the other is neutral. therefore, there will be increase in number of protons and the atom will be represented as follows.

according to periodic table, mass number of beryllium is 9 and it has atomic number 4 so, the atoms will be and .  

the protons and neutrons will be located inside the nucleus whereas the electrons will be revolving around the nucleus.