Question

14) the formula k2s indicates that a) the potassium ion is twice the size of the sulfide ion b) sulfur and potassium form a covalent bond c) there are two potassium ions for each ion of sulfur d) there are two sulfur ions for each ion of potassium 15) Fluorine, F, forms a binary ionic compound with lithium Li. What is the name of this compound? a) Fluorine lithide b) Lithium fluoride c)Lithium fluorine d) fluorine lithium 16) the standard on which the atomic mass unit is based is the mass of a a) proton b) neutron c) chlorine-35 atom d) carbon-12 atom 17)Two highly reactive elements in period 2 are the metal lithium and a) metalloid arsenic b) nonmetal selenium c) nonmetal fluorine d)nonmetal krypton

Pleeeeeaaaaseeee help

Answer 1

Answer: The correct option for 14 is c.

The correct option for 15 is b.

The correct option for 16 is d.

The correct option for 17 is c.

Explanation:

• For question 14.

The given formula is
`K_2S`. The ionization for this compound follows the equation:

`K_2S\rightarrow 2K^++S^(2-)`

From the above equation, it is clear that 2 potassium
`(K^+)` ions are needed for each sulfur ion.

Hence, the correct option is c.

• For question 15.

We are given a fluorine atom which forms a binary ionic compound with lithium atom.

The electronic configuration of fluorine having atomic number 9 is
`1s^22s^22p^5`. This element require 1 electron to obtain a stable electronic configuration. This will form an anion in an ionic compound.

The electronic configuration of lithium having atomic number 3 is
`1s^22s^1`. This element will loose 1 electron to obtain a stable electronic configuration. This will form a cation in an ionic compound.

Thus, these two form a binary ionic compound as the electron which is lost from lithium is accepted by fluorine, so it will result in the formation of compound having formula LiF which is termed as lithium fluoride.

Hence, the correct option is b.

• For question 16.

The atomic mass unit or AMU is defined as the
`(1)/(12)` mass of a carbon-12 atom.

Atomic mass is the sum of number of protons and neutrons in an element. Carbon has 6 neutrons and 6 protons.

Hence, the correct option is d.

• For question 17.

Reactivity is defined as the tendency to gain electrons in metals or the tendency to loose electrons in the case of non-metals.

Group 2 elements are Lithium, beryllium, born, carbon, nitrogen, oxygen, fluorine and neon.

From the above elements, the most reactive will be that element that will loose of gain electrons easily or which have the valency of 1.

The electronic configuration of fluorine having atomic number 9 is
`1s^22s^22p^5`. The valency of this element is 1 because it will gain 1 electron to obtain a stable electronic configuration.

Hence, the correct option is c.

Answer 2

14. Answer;

-There are two potassium ions for each ion of sulfur.

Step-by-step explanation;

The formula K2S indicates that there are two potassium ions for each ion of sulfur.

-K2S is the formula of potassium sulfide.

- From the formula; two potassium atoms combines with 1 atom of sulfur to form the compound. In other words the ratio of potassium and sulfur atoms in the compound is 2 : 1.

15. Answer;

-Lithium fluoride

Explanation;

-Fluorine, F, forms a binary ionic compound with lithium, Li. The name of the compound is lithium fluoride.

- A compound is a substance that is formed when two or more atoms from different elements are chemically bonded. For example Lithium fluoride is a compound that is made of fluorine atom and lithium atom that are chemically combined.

16. Answer;

-Carbon-12 atom

Explanation;

The standard on which the atomic mass unit is based is the mass of a carbon-12 atom.

-Atomic mass is the quantity of matter contained in an atom of an element. -The atomic mass is expressed as a multiple of one-twelfth the mass of the carbon-12 atom, which is assigned an atomic mass of 12 units.

17. Answer;

- Non-metal fluorine

Explanation;

-Two highly reactive elements in Period 2 are the metal lithium and the non-metal fluorine.

-Elements in period 2 often have the most extreme properties in their respective groups. Fluorine is the most reactive halogen, neon is the most inert noble gas, and lithium is the least reactive alkali metal, but the most reactive metal in group 2.