KHTN7 - ÔN TẬP HÓA HKII

đơn chất là từ

• From 2 elements.

• From 3 elements.

• From 4 or more elements.

• một nguyên tố hóa học

trong các dãy sau, đâu là dãy chất đơn chất?

• Fe(NO3)2, NO, C, S.

• Mg, K, S, C, N2.

• Fe, NO2, H2O.

• Cu(NO3)2, KCl, HCl.

The molecular weight of CO and Mg(OH)2 are (đơn vị amu)

• 28, 48

• 36,5, 78

• 17, 58

• 28 , 58 .

Which of the following is a chemical compound?

• O2.

• N2.

• H2.

• CO2.

đâu là đon chất?

• MnO2.

• N2O.

• H2.

• CO2.

Element X has an atomic weight of 3.5 times that of oxygen. What is element X?

• Ca

• Na

• K

• Fe

Covalent bonds are formed by

• weak electrostatic attraction between atoms.

• cặp electron dùng chung

• electron clouds.

• valence electrons.

phân tử KCl thuộc loại liên kết

• covalent bond.

• ionic bond.

• non-metal bond.

• metallic bond.

In the molecule O₂, the two oxygen atoms are bonded by:

• Ionic bond

• Covalent bond

• Hydrogen bond

• No bond

Which of the following molecules has an ionic bond?

• H₂

• H₂O

• MgO

• CO₂