Question

1. **which group contains an element which is liquid at stp?

a. 1
b. 2
c. 13
d. 15
e. 17

1. **the elements on the periodic table are arranged in order of increasing

a. boiling point
b. atomic number
c. electronegativity
d. atomic mass

1. **which of the following is an alkali metal?

a. h
c. cl
b. xe
d. cs

1. **which of the following is a noble gas?

a. li
c. ar
b. br
d. f

1. **which of the following is a halogen?

a. i
c. na
b. k
d. ne

Explanation:

1.

• Step1: Recall elements at STP

At STP (Standard Temperature and Pressure: \(0^{\circ}C\) and \(1\ atm\)), mercury (\(Hg\)) is a liquid metal. Mercury is in group 12 (which is sometimes considered as part of the broader transition - metal group, but if we consider the main - group numbering in some older or alternative systems, group 13 has gallium (\(Ga\)) which has a melting point of \(29.76^{\circ}C\) (very close to STP). Bromine (\(Br_2\)) is in group 17 and is a liquid at STP.

2.

• Step1: Recall periodic table arrangement

The modern periodic table is arranged in order of increasing atomic number (\(Z\)). The atomic number is the number of protons in an atom's nucleus.

3.

• Step1: Recall alkali metal properties

Alkali metals are in group 1 of the periodic table. Cesium (\(Cs\)) is in group 1. Hydrogen (\(H\)) is not considered an alkali metal in the traditional sense (it has different chemical properties compared to group 1 metals in many reactions). Chlorine (\(Cl\)) is a non - metal (halogen) and xenon (\(Xe\)) is a noble gas.

4.

• Step1: Recall noble gas group

Noble gases are in group 18 of the periodic table. Argon (\(Ar\)) is in group 18. Lithium (\(Li\)) is an alkali metal, bromine (\(Br\)) is a halogen, and fluorine (\(F\)) is a halogen.

5.

• Step1: Recall halogen group

Halogens are in group 17 of the periodic table. Iodine (\(I\)) is in group 17. Potassium (\(K\)) is an alkali metal, sodium (\(Na\)) is an alkali metal, and neon (\(Ne\)) is a noble gas.

Answer:

1. e. 17
2. b. atomic number
3. d. Cs
4. c. Ar
5. a. I