3 rd grade science

Question: An element has configuration 2, 8, 1. It belongs to, _________. 1. 1 group and 3 rd period 2. 3 group and 1 st period 3. 1 group and 8 th period 4. 17 group and 3 rd period Answer: ..

Question: The element, which has zero electron affinity in the 3 rd period is __________. 1. Al 2. P 3. Ar 4. S Answer: 3..

. If the plants are pure breeds producing only one type of offspring, they are called homozygous (TT or tt). If the plants produce both tall and short plants among the offspring, then they are heterozygous (Tt). In case of height, the tall plants of P generation are represented as TT and the short ..

In the case of these elements, all shells except the outermost shell are completely filled. Elements belonging to 1 (IA), 2 (IIA), 3 (IIIA), 4 (IVA), 5 (VA), 6 (VIA) and 7 (VIIA) are normal elements. Elements of the second period are known as typical elements [Li (Z = 3) to Ne ..

Maximum number of electrons that can be accommodated in a shell is given by 2n 2 where n = shell number For 1 st energy level, n = 1Maximum number of electrons in 1 st energy level = 2n 2 2 x (1) 2 = 2 For 2 nd energy level n = 2Maximum number of electrons in the 2 nd energy level = 2n..

Arrangement of Electrons in an Atom (Bohr-Bury Scheme) - Electrons revolve around the nucleus in different energy levels or shells and each shell is associated with definite energy. The energy of the K shell is the least while those of L, M, N and O shells increases progressively. We also know that..

Atomatic number of the elements 1st Period n = 1 Short period 2 Atomic number 1 and 2 2nd Period n = 2 Short period 8 Atomic number 3 to 10 3rd Period n = 3 Long period 8 Atomic number 11 to 18 4th Pe..

Calculate the mass of a body when a force of 225 N produces an acceleration of 2.5 m/s 2..

Question: A boy fires a gun and hears the echo 2 seconds later. If he is 480 m away from a wall, calculate the velocity of sound in air. Answer: v = = = 480 m s - 1..

Question: Calculate the distance covered and displacement of an object following the path as shown in the figure below. a) (b) (c) Answer: a) ACB is a semicircular path of radius r. Distance covered = circumference of the hemisphere = p r displacement = diameter = 2r. (i.e., the ..