An atom has 26 protons, 26 electrons and 30 neutrons. The atom has

1.   atomic number 26, mass number 52
2. atomic number 56, mass number 30
3. atomic number 30, mass number 82
4. atomic number 52, mass number 56
5. atomic number 26, mass number 56.

   The Brownian movement is taken to be the evidence of the:

1. theory of association of water molecules
2. theory of ionization of electrolytes
3. theory of colloidal suspensions
4. kinetic theory of behavior of substances
5. Brownian theory.

   One off the isotopes of an element X has an atomic number Z and a mass number A. What is the number of neutrons contained in the nucleus of the element X?

1. Z
2. A
3. A + Z
4. A – Z
5. Z – A

Which of the following set of nuclide notation represents isotopes? 

1. ¹⁸ X ¹⁶ X ¹⁹ x 
2. ¹⁸ X ¹⁸ X X 
3.  ¹⁶ x ¹⁸ x ¹⁸90x 
4.  ¹⁶ X ¹⁷89x,

What is the maximum number of electrons in the innermost shell of atoms?

1. 3
2. 1
3. 4
4. 2
5. 8

A certain element has atomic number W and mass number Y. The number of neutrons contained in its nucleus is:

1. W
2. W-Y
3. Y-W
4. Y+W

A certain element has atomic number W and mass number Y. The number of neutrons contained in its nucleus is:

1. W
2. W-Y
3. Y-W
4. Y+W

Which neutral atom has the same number of eletrons as Mg²+?

1. Magnesium
2. Sodium
3. Neon
4. Argon

How many numbers of shells are there in Magnesium atom?

1.  1 
2.  2
3.  3
4.  4

Isotopes are atoms of the same element that have different:

1. Atomic number
2. Electron arrangement
3. Mass number
4. Protons

   Chlorine ion, Cl^- differs from chlorine atom because it has       

1.   more protons. 
2.  less protons. 
3.  more electrons. 
4.  less electrons. 
5.  more neutrons.

Which of the following sets represents isotopes of an element?

A.      Z, and 

B.    Z, and 

C.    Z, and 

D.   Z, and 

E.  Z, and 

   Which of the following is the electronic configuration of an element Y found in period 3 and group II of the periodic table?

1.  2:8 
2.  2:8:2    
3.  2:6
4. 2:8:8:2   
5. 2:8:4 

The mass number of a carbon atom that contains six protons, eight neutrons, and six electrons is

1. 6
2. 14
3. 8
4. 12
5. 20.

Which group and period does the element with 11 electrons belong?

1. Group I and period 3
2. Group II and period 1
3. Group I and period 1
4. Group II and period 3.

The mass number of an atom is determined by:

1. protons and neutrons
2. protons and electrons
3. neutrons and electrons
4. protons alone

When an atom loses or gains electron, it becomes:

1. An ion 
2. An anion
3. A cation 
4. A charged ion

An isotope of carbon has an atomic number 6 and a mass number of 14, this means that it has:

1. 6 protons, 8 neutrons, 6 electrons
2. 8 protons, 6 neutrons, 8 neutrons
3. 6 protons, 14 neutrons, 6 electrons
4. 14 protons, 6 neutrons, 14 electrons.

Atomic structures of all elements consist of electrons, protons and neutrons except that of

1. Hyadrogen
2. Nitrogen
3. Oxygen
4. Carbon

 (b)  Fill in the missing value in the following table.

11. (a) Elements A, B, C and D have atomic numbers 6, 8, 17 and 20 respectively. Write electronic structures of these elements. (4 marks)

   (b) Fill in the blank spaces by using the appropriate terms

(i)     In an atom, the effect of the charged nucleons is balanced by the charge of……………..

(a) Match each item in List A with a correct response in List B by writing its letter below the number of the corresponding item in the table provided.

(b) Fill in the blank spaces with the correct answer.

(i) A reaction that releases energy in the form of light and heat is called..........

(ii)A chemical process that occurs in steel and iron in the presence of air and water is known as..........

(iii)Oxygen, heat and fuel are the three components that make..........

(iv)Injuries that result from the body coming into contact with heat of harmful chemicals are called..........

(v)A solution which can dissolve no more solute at a given temperature is called . . . . . . . . . . .

7. (a) (i) How many electrons and protons are present in oxygen element and aluminium element?

(ii) Write the electronic configuration of chlorine ion.

(b) Use the elements with chemical symbols: P, S and Cl to answer the following questions:

(i)Which elements is the most electronegative?

(ii)Mention the least electronegative element.

(iii)Which element has the largest atomic structure?

(c)Study the following table with elements lettered F, G, L, M and J, then answer the questions that follow:

(i)How many neutrons are present in element L?

(ii)Which group and period of the periodic table does element F belong?

(iii)Which element does not readily form compounds? Give a reason.

Draw diagrams to show the atomic structures of the elements with atomic number l , 10, 16 and 19.

Element X has 20 electrons and a mass number of 40. Work out the number of each type of nucleons present. (7 marks)

A certain compound having a relative molecular mass of 76 was found to contain 15.8% of carbon and 84.2% of sulphur. Based on this information:

(a)determine the empirical formula and molecular formula of the compound.

2. Match each item in List A with a correct response in List B by writing its letter bellow the number of the corresponding item in the table provided.

2. Match each item in List A with a correct response in List B by writing its letter bellow the number of the corresponding item in the table provided.

(c)       Give the chemical formula for the combination of the following sets of ions:

(i)       Mg²+, PO}(ii) Fe³+, soi-

(a)(i)Using Dalton atomic theory, explain the fact that calcium sulphate from Tanzania and that found in Kenya has the same percentage by mass of calcium, sulphur and oxygen.

(ii) Why isotopes of the same element have similar chemical properties?

(iii)Matter is made up of tiny indivisible particle called atoms. With reason, support or oppose this statement.

(b) An isotope of strontium (Sr) has mass number and atomic number 38

1. Write its nuclide notation
2. How many neutrons does it have
3. How many protons does it have?
4. How many electrons does it have?

 (b)   Elements K, L, M and N have atomic numbers 6, 8, 9 and 20 respectively. Classify each element into its respective period and group.

2. Match the items in LIST A with the responses in LISTB by writing the letter of the correct response beside the item number in the answer booklet provided.

9. (a)An atom M has an atomic number 14 and mass number 28. 

(i)What is the number of protons and neutrons?

 (ii) Write the electronic configuration of atom M.

Match the items in List A with the responses in List B by writing the letter of the correct response beside the item number in the answer booklet provide.