Across period 3 from Na to Cl, which property shows a continuous increase?

1. Electronegativity is the tendency to attract shared electrons. 2. Across period 3 atomic size shrinks because protons grow faster than added electrons. 3. Smaller atoms pull shared pairs more tightly. 4. So electronegativity grows steadily from Na to Cl. 5. Atomic radius and metallic character both decrease across the period. 6. The shell count stays the same in a single period. 7. Hence the only property that rises continuously is electronegativity. _Source: Selina Concise Chemistry ICSE Class 10, Ch 1 'Periodic Table' (aplustopper.com extract)_