period 4, p- block
period 3, p- block
period 4, d- block
period 3, d- block
Correct answer is A
Selenium is a chemical element with the symbol Se and atomic number 34. It is a non-metal
Which of the following statements about atoms of a metal is correct? They
readily accept electrons
are soft
are held together by covalent bond
are held together by a sea of electron cloud
Correct answer is D
Metals are effectively lots of positively charged ions with a cloud/sea of delocalised electrons. This means the electrons are free to move throughout the metal, and is also why metals can conduct electricity as the electrons can move. The more delocalised electrons a metal has, the stronger it will be held together.
alkaline
amphoteric
acidic
neutral
Correct answer is B
An amphoteric oxide is an oxide that can act as either an acid or base in a reaction to produce a salt and water.
The electron configuration of carbon atom in its excited state is
1s\(^{2}\)2s\(^{2}\)2px\(^{2}\)2py\(^{0}\)
1s\(^{2}\)2s\(^{2}\)2px\(^{1}\)2py\(^{1}\)
1s\(^{2}\)2s\(^{1}\)2px\(^{1}\)2py\(^{1}\)2pz\(^{1}\)
1s\(^{1}\)2s\(^{2}\)2px\(^{1}\)2py\(^{1}\)
Correct answer is C
- So any electron configuration in which the last electron (again, the valence electron) is in a higher energy orbital, this element is said to be in an excited state.
- When a carbon atom becomes excited by absorbing energy, one of its 2s electrons is promoted into the 2p sublevel.
I and III only
I and II only
II and IV only
I, II, III and IV
Correct answer is C
- Ionization behaviour; The atoms of non-metals usually have four to seven valence electrons. They have a great tendency to ionize by accepting electrons to form negative ions.
- Reaction with acids; A metal which is more electro positive than hydrogen readily displaces the hydrogen ion, H+, from an acid.