All questions
- Which is not a property of living being? a. Metabolism b. Decay c. Growth d. Reproduction correct option is b. Decay 2
- The angle of 1" (second of arc) in a radian is equal to: (1) 4.85 × 10–4 (2) 4.85 × 10–6 (3) 1.75 × 10–2 (4) 1.75 × 10–4 A minute of arc is πover 10800 of a radian. A second of arc, arcsecond (arcsec), or arc second, denoted by the symbol ″, is 1over60 of an ar... 1
- How the atomic size vary in a group and across a period? Explain with suitable example. Answer: Atomic size increases down a group and decreases from left to right across a period. Down a group: each new element has one more she... 1
- Define ionization enthalpy. Name the factors on which ionisation enthalpy depends? How does it vary down the group and across a period? Variation of ionization energy down the group: On moving down the group, the ionization enthalpy decreases. This is because the electron is... 2
- What are the valence electrons ? For s-block and p-block elements show that number of valence electrons is equal to its group number. Electrons present in the outermost shell of the atom of an element are called valence electrons. 3Li is an s-block element and its electroni... 1
- Compare chemical properties of metals and non metals. The difference in chemical properties between metals and nonmetals. Nonmetals Metals 1. Nonmetals form acidic or neutral oxides when they re... 1
- Explain : electronegativity and electron gain enthalpy. Which of the two can be measured experimentally? The ability of a covalently bonded atom to attract the shared electrons toward itself is called electronegativity (EN). Electronegativity ca... 1
- Why the elements belonging to the same group do have similar chemical properties ? Chemical properties of elements depend upon their valency.Elements belonging to the same group have the same valency. Hence, the elements be... 1
- Why the second ionization enthalpy is greater than the first ionization enthalpy ? The second ionization enthalpy (Δ_iH₂) is greater than the first ionization enthalpy (Δ_iH₁) as it involves removal of electron from the pos... 1
- Explain the screening effect with a suitable example. In a multi-electron atom, the electrons in the inner shells tend to prevent the attractive influence of the nucleus from reaching the outerm... 1
- Ionization enthalpy of Li is 520 kJ mol-1 while that of F is 1681 kJ mol-1. Explain. Both Li and F belong to period 2. Across a period, the screening effect is the same while the effective nuclear charge increases. As a resul... 1
- La belongs to group 3 while Hg belongs to group 12 and both belong to period 6 of the periodic table. La and Hg both belong to period 6. Therefore, n = 6. Elements of group 3 to group 12 belong to the d-block of the modern periodic table. The... 1
- Write a e-mail, addressed to the class teachers and informing class teachers of a school about their Sample e-mail informing class teachers about the meeting on dress code From: discipline@abcschool.edu.in To: classteachers@abcschool.edu.in... 1
- Write a e-mail, addressed to the principals of different schools located in the district/zone and informing the students Sample e-mail inviting schools to a three-day tree plantation campaign From: greencampaign.district@gmail.com To: principals.zone2@gmail.com... 1
- You are the Principal of the school. Write an e-mail to parents of the students of classes IX-XII about the same.
- Write a e-mail to all the residents and the members of the Gautam Nagar Residents’ Welfare Society giving information on the event.
- Write an e-mail to a prominent football coach of your city who has agreed to be the referee at the event, giving all relevant details.
- Write a e-mail instructing the residents of a colony to maintain cleanliness in the park in their neighbourhood. Sample e-mail requesting residents to keep the neighbourhood park clean From: secretary.rwa.greenpark@gmail.com To: seniorcitizens.greenpark... 1
- Write an e-mail to the General Manager of the supermarket seeking permission to display the notice and requesting a sponsorship for the event.
- Write an e-mail, addressing teachers in-charge of different classes that will participate in the function. Sample e-mail announcing auditions for the dramatics competition From: culturalsecretary@abcschool.edu.in To: classteachers@abcschool.edu.in... 1
- Write an e-mail informing the office-bearers of a school’s Science Society about their meeting To: (e-mail ids of office bearers of the Science Society at Abalus Public School, Husainganj, Lucknow) Cc: (e-mail ids of other staff member... 1
- Write an E-mail addressing all students and teachers, and informing them about the fair and informing students To: (e-mail ids of students/class teachers concerned) Subject: Charity Fair is being organized for anath ashram {or any needy group of peopl... 1
- Write a request letter to your headmaster to start yoga classes in school. 207, ram nivas bhagat singh road, Dombivali, {Date here} To, The Headmaster, Subhash chandra bose Vidyalaya, dombivali (E), Thane - 421201 S... 2
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