Chemistry

Periodic Classification and Elements

1,176 Questions

Periodic classification organizes chemical elements based on atomic structure, periodic laws, and elemental properties. It covers historical classification systems, electron configurations, and periodic trends. Test takers preparing for chemistry sections will find these questions crucial for mastering fundamental element properties and atomic interactions.

Periodic table structureAtomic orbitalsElement identificationPeriodic laws

Periodic Classification and Elements Questions

Multiple choice nuclear reactions nuclear structure nuclei atomic nuclei physics

Consider the following statements
(i)All isotopes of an element have the same number of neutrons
(ii)Only one isotope of an element can be stable and non -radioactive
(iii)All elements have isotopes  
(iv)All isotopes of Carbon can form chemical compounds with Oxygen -16
The correct option regarding an isotope is 

  1. (iii) and (iv) only

  2. (ii),(iii) and (iii) only

  3. (i),(ii) and (iii) only

  4. (i),(iii) and (iv) only
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

A

Isotopes are atoms of the same element having the same numbers of protons and different numbers of neutrons. All elements have isotope. Also all isotope of carbon can form chemical compounds with oxygen - 16.

Multiple choice chemistry metals physical properties of metals and non-metals some physical properties of metals general characteristics and uses of metals

Metals generally have ______ number of electron(s) in their valence shell.

  1. 1, 2, or 3

  2. 7, 8 or 9

  3. 10, 11, or 12

  4. 20, 30, or 40
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Alkali and alkaline earth metals have valence electrons as 1 and 2 respectively. In general, elements with 1-3 valence electrons can be metal except for hydrogen and helium (nonmetal) and Boron (metalloid). Also, transition elements have 2 valence electrons but since they can utilize d-orbital for bonding, therefore can have variable oxidation states.
Therefore in general  1-3 valence electrons can be meta.
Hence, option $A$ is correct.

Multiple choice commercial applications global environmental change causes of resource depletion causes of greenhouse effect ozone layer depletion

Which type of electron is present in free radical?

  1. Unpaired and extremely reactive

  2. Paired and extremely inactive

  3. Unpaired and extremely inactive

  4. Paired and extremely reactive
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Free radicals have unpaired electrons. These are extremely reactive. As one chlorine free radical can remove 11000 ozone molecules from stratosphere.

Multiple choice chemistry materials: metals and non-metals physical properties of non-metals uses of metals and non metals physical properties of metals and non-metals

The metallic character of elements ............. in a group from top to bottom.

  1. Increases

  2. Decreases

  3. remains constant

  4. shows indefinite behaviour
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

As you move down a group in the periodic table, the atomic size increases and the valence electrons are further from the nucleus, making them easier to lose, which increases metallic character.

Multiple choice

Ag is the symbol of which chemical element?

  1. Argon

  2. Silver

  3. Titanum

  4. Iron
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Ag is the chemical symbol for Silver (from Latin 'argentum'). Argon is Ar, Titanium is Ti, and Iron is Fe. This question contains a typo in option C ('Titanum' should be 'Titanium').

Multiple choice

The number above each element represents what?

  1. neutrons in the nuclei

  2. protons in the nuclei

  3. electrons in the nuclei

  4. no correct answers
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

The atomic number, which is the number displayed above each element on the periodic table, represents the number of protons in the nucleus of an atom of that element.

Multiple choice

How many states of matter are there on the periodic table?

  1. two

  2. three

  3. four

  4. one hundred three
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

The three classical states of matter represented on the periodic table at room temperature are solid, liquid, and gas. While plasma is a fourth state, it is not typically shown in standard periodic table representations.